1
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Wang L, Nughays R, Yin J, Shih CH, Guo TF, Mohammed OF, Chergui M. Band Gap Renormalization at Different Symmetry Points in Perovskites. ACS PHOTONICS 2024; 11:2273-2281. [PMID: 38911840 PMCID: PMC11191737 DOI: 10.1021/acsphotonics.4c00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 06/25/2024]
Abstract
Using ultrafast broad-band transient absorption (TA) spectroscopy of photoexcited MAPbBr3 thin films with probe continua in the visible and the mid- to deep-ultraviolet (UV) ranges, we capture the ultrafast renormalization at the fundamental gap at the R symmetry point of the Brillouin zone (BZ) and a higher energy gap at the M symmetry point. Advanced global lifetime analysis and lifetime density distribution analysis are applied to extract quantitative information. Our work confirms the similarity of the response at both high-symmetry points, which indicates a band edge renormalization that rises within the instrument response function (IRF, ∼250 fs) and decays in ca. 400-600 fs, undergoing an energy red shift of 90-150 meV. The reported time scale corresponds to the decay of free carriers into neutral excitons. The ability to monitor different high-symmetry points in photoexcited perovskites opens exciting prospects for the characterization of a large class of materials and for photonic applications.
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Affiliation(s)
- Lijie Wang
- Lausanne
Centre for Ultrafast Science (LACUS), ISIC, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Advanced
Membranes and Porous Materials Center (AMPM), Division of Physical
Science and Engineering, King Abdullah University
of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Razan Nughays
- Advanced
Membranes and Porous Materials Center (AMPM), Division of Physical
Science and Engineering, King Abdullah University
of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Jun Yin
- Department
of Applied Physics, The Hong Kong Polytechnic
University, Kowloon 999077, Hong Kong, P. R. China
| | - Chun-Hua Shih
- Department
of Photonics, National Cheng Kung University, Tainan 701, Taiwan
| | - Tzung-Fang Guo
- Department
of Photonics, National Cheng Kung University, Tainan 701, Taiwan
| | - Omar F. Mohammed
- Advanced
Membranes and Porous Materials Center (AMPM), Division of Physical
Science and Engineering, King Abdullah University
of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
- KAUST
Catalysis Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology
(KAUST), Thuwal 23955-6900, Kingdom of Saudi
Arabia
| | - Majed Chergui
- Lausanne
Centre for Ultrafast Science (LACUS), ISIC, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Elettra
Sincrotrone Trieste, Strada Statale 14 - km 163,5, 34149 Basovizza, Trieste, Italy
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2
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Pada Sarker H, Abild-Pedersen F, Bajdich M. Prediction of Feasibility of Polaronic OER on (110) Surface of Rutile TiO 2. Chemphyschem 2024; 25:e202400060. [PMID: 38427793 DOI: 10.1002/cphc.202400060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/23/2024] [Accepted: 02/28/2024] [Indexed: 03/03/2024]
Abstract
The polaronic effects at the atomic level hold paramount significance for advancing the efficacy of transition metal oxides in applications pertinent to renewable energy. The lattice-distortion mediated localization of photoexcited carriers in the form of polarons plays a pivotal role in the photocatalysis. This investigation focuses on rutile TiO2, an important material extensively explored for solar energy conversion in artificial photosynthesis, specifically targeting the generation of green H2 through photoelectrochemical (PEC) H2O splitting. By employing Hubbard-U corrected and hybrid density functional theory (DFT) methods, we systematically probe the polaronic effects in the catalysis of oxygen evolution reaction (OER) on the (110) surface of rutile TiO2. Theoretical understanding of polarons within the surface, coupled with simulations of OER at distinct titanium (Ti) and oxygen (O) active sites, reveals diverse polaron formation energies within the lattice sites with strong preference for bulk and surface bridge (Ob) oxygen sites. Moreover, we provide the evidence for the facilitative role of polarons in OER. We find that hole polarons situated at the equatorial oxygen sites near the Ti-active site, along with bridge site hole polarons distal from the Ob active site yield a small reduction in OER overpotential by ~0.06 eV and ~0.12 eV, respectively. However, subsurface, equatorial, and bridge site hole polarons significantly reduce the Ti-active site OER overpotential by ~0.4 eV through the peroxo-type oxygen pathway. We also observe that the presence of hole polarons stabilizes the *OH, *O, and *OOH intermediate species compared to the scenario without hole polarons. Overall, this study provides a detailed mechanistic insight into polaron-mediated OER, offering a promising avenue for improving the catalytic activity of transition metal oxide-based photocatalysts catering to renewable energy requisites.
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Affiliation(s)
- Hori Pada Sarker
- Liquid Sunlight Alliance (LiSA), California Institute of Technology, Pasadena, CA, 91125, USA
- Department of Chemical Engineering, Stanford University, 43 Via Ortega, Stanford, CA, 94305, USA
- SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Frank Abild-Pedersen
- Liquid Sunlight Alliance (LiSA), California Institute of Technology, Pasadena, CA, 91125, USA
- SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Michal Bajdich
- Liquid Sunlight Alliance (LiSA), California Institute of Technology, Pasadena, CA, 91125, USA
- SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
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3
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Ulstrup S, In 't Veld Y, Miwa JA, Jones AJH, McCreary KM, Robinson JT, Jonker BT, Singh S, Koch RJ, Rotenberg E, Bostwick A, Jozwiak C, Rösner M, Katoch J. Observation of interlayer plasmon polaron in graphene/WS 2 heterostructures. Nat Commun 2024; 15:3845. [PMID: 38714749 DOI: 10.1038/s41467-024-48186-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 04/22/2024] [Indexed: 05/10/2024] Open
Abstract
Harnessing electronic excitations involving coherent coupling to bosonic modes is essential for the design and control of emergent phenomena in quantum materials. In situations where charge carriers induce a lattice distortion due to the electron-phonon interaction, the conducting states get "dressed", which leads to the formation of polaronic quasiparticles. The exploration of polaronic effects on low-energy excitations is in its infancy in two-dimensional materials. Here, we present the discovery of an interlayer plasmon polaron in heterostructures composed of graphene on top of single-layer WS2. By using micro-focused angle-resolved photoemission spectroscopy during in situ doping of the top graphene layer, we observe a strong quasiparticle peak accompanied by several carrier density-dependent shake-off replicas around the single-layer WS2 conduction band minimum. Our results are explained by an effective many-body model in terms of a coupling between single-layer WS2 conduction electrons and an interlayer plasmon mode. It is important to take into account the presence of such interlayer collective modes, as they have profound consequences for the electronic and optical properties of heterostructures that are routinely explored in many device architectures involving 2D transition metal dichalcogenides.
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Affiliation(s)
- Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark.
| | - Yann In 't Veld
- Institute for Molecules and Materials, Radboud University, 6525 AJ, Nijmegen, the Netherlands
| | - Jill A Miwa
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
| | - Alfred J H Jones
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
| | | | | | | | - Simranjeet Singh
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Roland J Koch
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Malte Rösner
- Institute for Molecules and Materials, Radboud University, 6525 AJ, Nijmegen, the Netherlands.
| | - Jyoti Katoch
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
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4
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Yang Y, Lau KY, Zheng J, Dong J, Wang L, Yin X, Tong Z, Qiu H, Xu J, Xiao W, Xu B, Qiu J, Hosono H, Liu X. Polaronic Nonlinear Optical Response and All-Optical Switching Based on an Ionic Metal Oxide. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306226. [PMID: 38037680 DOI: 10.1002/smll.202306226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 11/08/2023] [Indexed: 12/02/2023]
Abstract
It has been well-established that light-matter interactions, as manifested by diverse linear and nonlinear optical (NLO) processes, are mediated by real and virtual particles, such as electrons, phonons, and excitons. Polarons, often regarded as electrons dressed by phonons, are known to contribute to exotic behaviors of solids, from superconductivity to photocatalysis, while their role in materials' NLO response remains largely unexplored. Here, the NLO response mediated by polarons supported by a model ionic metal oxide, TiO2, is examined. It is observed that the formation of polaronic states within the bandgap results in a dramatic enhancement of NLO absorption coefficient by over 130 times for photon energies in the sub-bandgap regions, characterized by a 100 fs scale ultrafast response that is typical for thermalized electrons in metals. The ultrafast polaronic NLO response is then exploited for the development of all-optical switches for ultrafast pulse generation in near-infrared (NIR) fiber lasers and modulation of optical signal in the telecommunication band based on evanescent interaction on a planar waveguide chip. These results suggest that the polarons supported by dielectric ionic oxides can fill the gaps left by dielectric and metallic materials and serve as a novel platform for nonlinear photonic applications.
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Affiliation(s)
- Yuting Yang
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Kuen Yao Lau
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215006, China
| | - Jingying Zheng
- School of Material Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Junhao Dong
- School of Material Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Lin Wang
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaojie Yin
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Shijia Photonics Technology, Hebi, 458030, China
| | - Zhaojing Tong
- School of Electrical Engineering and Automation, Henan Polytechnic University, Jiaozuo, 454003, China
| | - Hangkai Qiu
- ULTRON Photonics Inc., Hangzhou, 311202, China
| | - Jian Xu
- Technology Center, China Tobacco Zhejiang Industrial Co., Ltd, Hangzhou, 310001, China
| | - Weiqiang Xiao
- Technology Center, China Tobacco Zhejiang Industrial Co., Ltd, Hangzhou, 310001, China
| | - BeiBei Xu
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215006, China
| | - Jianrong Qiu
- School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, 215006, China
| | - Hideo Hosono
- Materials Research Center for Element Strategy (MCES), Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - Xiaofeng Liu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
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5
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Celiberti L, Fiore Mosca D, Allodi G, Pourovskii LV, Tassetti A, Forino PC, Cong R, Garcia E, Tran PM, De Renzi R, Woodward PM, Mitrović VF, Sanna S, Franchini C. Spin-orbital Jahn-Teller bipolarons. Nat Commun 2024; 15:2429. [PMID: 38499529 DOI: 10.1038/s41467-024-46621-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 03/04/2024] [Indexed: 03/20/2024] Open
Abstract
Polarons and spin-orbit (SO) coupling are distinct quantum effects that play a critical role in charge transport and spin-orbitronics. Polarons originate from strong electron-phonon interaction and are ubiquitous in polarizable materials featuring electron localization, in particular 3d transition metal oxides (TMOs). On the other hand, the relativistic coupling between the spin and orbital angular momentum is notable in lattices with heavy atoms and develops in 5d TMOs, where electrons are spatially delocalized. Here we combine ab initio calculations and magnetic measurements to show that these two seemingly mutually exclusive interactions are entangled in the electron-doped SO-coupled Mott insulator Ba2Na1-xCaxOsO6 (0 < x < 1), unveiling the formation of spin-orbital bipolarons. Polaron charge trapping, favoured by the Jahn-Teller lattice activity, converts the Os 5d1 spin-orbital Jeff = 3/2 levels, characteristic of the parent compound Ba2NaOsO6 (BNOO), into a bipolaron 5d2 Jeff = 2 manifold, leading to the coexistence of different J-effective states in a single-phase material. The gradual increase of bipolarons with increasing doping creates robust in-gap states that prevents the transition to a metal phase even at ultrahigh doping, thus preserving the Mott gap across the entire doping range from d1 BNOO to d2 Ba2CaOsO6 (BCOO).
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Affiliation(s)
- Lorenzo Celiberti
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, 1090, Vienna, Austria
- Department of Physics and Astronomy, Università di Bologna, 40127, Bologna, Italy
| | - Dario Fiore Mosca
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, 1090, Vienna, Austria
- CPHT, CNRS, École polytechnique, Institut Polytechnique de Paris, 91120, Palaiseau, France
- Collège de France, Université PSL, 11 place Marcelin Berthelot, 75005, Paris, France
| | - Giuseppe Allodi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, 43124, Parma, Italy
| | - Leonid V Pourovskii
- CPHT, CNRS, École polytechnique, Institut Polytechnique de Paris, 91120, Palaiseau, France
- Collège de France, Université PSL, 11 place Marcelin Berthelot, 75005, Paris, France
| | - Anna Tassetti
- Department of Physics and Astronomy, Università di Bologna, 40127, Bologna, Italy
| | | | - Rong Cong
- Department of Physics, Brown University, Providence, RI, 02912, USA
| | - Erick Garcia
- Department of Physics, Brown University, Providence, RI, 02912, USA
| | - Phuong M Tran
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Roberto De Renzi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, 43124, Parma, Italy
| | - Patrick M Woodward
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Vesna F Mitrović
- Department of Physics, Brown University, Providence, RI, 02912, USA
| | - Samuele Sanna
- Department of Physics and Astronomy, Università di Bologna, 40127, Bologna, Italy
| | - Cesare Franchini
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, 1090, Vienna, Austria.
- Department of Physics and Astronomy, Università di Bologna, 40127, Bologna, Italy.
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6
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Mihalyuk AN, Bondarenko LV, Tupchaya AY, Gruznev DV, Solovova NY, Golyashov VA, Tereshchenko OE, Okuda T, Kimura A, Eremeev SV, Zotov AV, Saranin AA. Emergence of quasi-1D spin-polarized states in ultrathin Bi films on InAs(111)A for spintronics applications. NANOSCALE 2024; 16:1272-1281. [PMID: 38126765 DOI: 10.1039/d3nr03830k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The discovery, characterization, and control of heavy-fermion low-dimensional materials are central to nanoscience since quantum phenomena acquire an exotic and highly tunable character. In this work, through a variety of comprehensive experimental and theoretical techniques, it was observed and predicted that the synthesis of ultrathin Bi films on the InAs(111)A surface produces quasi-one-dimensional spin-polarized states, providing a platform for the realization of a unique spin-transport regime in the system. Scanning tunneling microscopy and low-energy electron diffraction measurements revealed that the InAs(111)A substrate facilitates the formation of the Bi-dimer phase of 2√3 × 3 periodicity with an admixture of the Bi-bilayer phase under submonolayer Bi deposition. X-ray photoelectron spectroscopy (XPS) measurements have shown the chemical stability of the Bi-induced phases, while spin and angle resolved photoemission spectroscopy (SARPES) observations combined with state-of-the-art DFT calculations have revealed that the electronic spectrum of the Bi-dimer phase holds a quasi-1D hole-like spin-split state at the Fermi level with advanced spin texture, whereas the Bi-bilayer phase demonstrates metallic states with large Rashba spin-splitting. The band structure of the Bi/InAs(111)A interface is discovered to hold great potential as a high-performance spintronics material fabricated in the ultimate two-dimensional limit.
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Affiliation(s)
- Alexey N Mihalyuk
- Institute of High Technologies and Advanced Materials, Far Eastern Federal University, 690950 Vladivostok, Russia.
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Leonid V Bondarenko
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Alexandra Y Tupchaya
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Dimitry V Gruznev
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | | | - Vladimir A Golyashov
- Novosibirsk State University, 630090 Novosibirsk, Russia
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Oleg E Tereshchenko
- Novosibirsk State University, 630090 Novosibirsk, Russia
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Taichi Okuda
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Akio Kimura
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM2), 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Sergey V Eremeev
- Institute of Strength Physics and Materials Science, Tomsk 634055, Russia
| | - Andrey V Zotov
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Alexander A Saranin
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
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7
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Wang A, Jiang X, Zheng Q, Petek H, Zhao J. Ultrafast many-body bright-dark exciton transition in anatase TiO 2. Proc Natl Acad Sci U S A 2023; 120:e2307671120. [PMID: 37956295 PMCID: PMC10666115 DOI: 10.1073/pnas.2307671120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 09/29/2023] [Indexed: 11/15/2023] Open
Abstract
The momentum-forbidden dark excitons can have a pivotal role in quantum information processing, Bose-Einstein condensation, and light-energy harvesting. Anatase TiO2 with an indirect band gap is a prototypical platform to study bright to momentum-forbidden dark exciton transition. Here, we examine, by GW plus the real-time Bethe-Salpeter equation combined with the nonadiabatic molecular dynamics (GW + rtBSE-NAMD), the many-body transition that occurs within 100 fs from the optically excited bright to the strongly bound momentum-forbidden dark excitons in anatase TiO2. Comparing with the single-particle picture in which the exciton transition is considered to occur through electron-phonon scattering, within the GW + rtBSE-NAMD framework, the many-body electron-hole Coulomb interaction activates additional exciton relaxation channels to notably accelerate the exciton transition in competition with other radiative and nonradiative processes. The existence of dark excitons and ultrafast bright-dark exciton transitions sheds insights into applications of anatase TiO2 in optoelectronic devices and light-energy harvesting as well as the formation process of dark excitons in semiconductors.
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Affiliation(s)
- Aolei Wang
- Department of Physics, University of Science and Technology of China, Hefei230026, China
| | - Xiang Jiang
- International Center for Quantum Design of Functional Materials/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei230026, China
| | - Qijing Zheng
- Department of Physics, University of Science and Technology of China, Hefei230026, China
| | - Hrvoje Petek
- Department of Physics and Astronomy and the IQ Initiative, University of Pittsburgh, Pittsburgh, PA15260
| | - Jin Zhao
- Department of Physics, University of Science and Technology of China, Hefei230026, China
- International Center for Quantum Design of Functional Materials/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei230026, China
- Department of Physics and Astronomy and the IQ Initiative, University of Pittsburgh, Pittsburgh, PA15260
- Hefei National Laboratory, University of Science and Technology of China, Hefei230088, China
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8
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Ren Z, Shi Z, Feng H, Xu Z, Hao W. Recent Progresses of Polarons: Fundamentals and Roles in Photocatalysis and Photoelectrocatalysis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023:e2305139. [PMID: 37949811 DOI: 10.1002/advs.202305139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/21/2023] [Indexed: 11/12/2023]
Abstract
Photocatalysis and photoelectrocatalysis are promising ways in the utilization of solar energy. To address the low efficiency of photocatalysts and photoelectrodes, in-depth understanding of their catalytic mechanism is in urgent need. Recently, polaron is considered as an influential factor in catalysis, which brings researchers a new approach to modify photocatalysts and photoelectrodes. In this review, brief introduction of polaron is given first, followed by which models and recent experimentally observations of polarons are reviewed. Studies about roles of polarons in photocatalysis and photoelectrocatalysis are listed in order to provide some inspiration in exploring the mechanism and improving the efficiency of photocatalysis and photoelectrocatalysis.
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Affiliation(s)
- Zhizhen Ren
- School of Physics, Beihang University, Beijing, 100191, China
| | - Zhijian Shi
- School of Physics, Beihang University, Beijing, 100191, China
| | - Haifeng Feng
- School of Physics, Beihang University, Beijing, 100191, China
| | - Zhongfei Xu
- College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Weichang Hao
- School of Physics, Beihang University, Beijing, 100191, China
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9
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Liu H, Wang A, Zhang P, Ma C, Chen C, Liu Z, Zhang YQ, Feng B, Cheng P, Zhao J, Chen L, Wu K. Atomic-scale manipulation of single-polaron in a two-dimensional semiconductor. Nat Commun 2023; 14:3690. [PMID: 37344475 DOI: 10.1038/s41467-023-39361-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023] Open
Abstract
Polaron is a composite quasiparticle derived from an excess carrier trapped by local lattice distortion, and it has been studied extensively for decades both theoretically and experimentally. However, atomic-scale creation and manipulation of single-polarons in real space have still not been achieved so far, which precludes the atomistic understanding of the properties of polarons as well as their applications. Herein, using scanning tunneling microscopy, we succeeded to create single polarons in a monolayer two-dimensional (2D) semiconductor, CoCl2. Combined with first-principles calculations, two stable polaron configurations, centered at atop and hollow sites, respectively, have been revealed. Remarkably, a series of manipulation progresses - from creation, erasure, to transition - can be accurately implemented on individual polarons. Our results pave the way to understand the physics of polaron at atomic level, and the easy control of single polarons in 2D semiconductor may open the door to 2D polaronics including the data storage.
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Affiliation(s)
- Huiru Liu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Aolei Wang
- Department of Physics, University of Science and Technology of China, 230026, Hefei, Anhui, China
| | - Ping Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Chen Ma
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Caiyun Chen
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Zijia Liu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Yi-Qi Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Baojie Feng
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China
| | - Peng Cheng
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Jin Zhao
- Department of Physics, University of Science and Technology of China, 230026, Hefei, Anhui, China.
- ICQD/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, Anhui, China.
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, 15260, PA, USA.
- Hefei National Laboratory, University of Science and Technology of China, 230088, Hefei, Anhui, China.
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, 100871, Beijing, China.
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10
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Cai M, Miao MP, Liang Y, Jiang Z, Liu ZY, Zhang WH, Liao X, Zhu LF, West D, Zhang S, Fu YS. Manipulating single excess electrons in monolayer transition metal dihalide. Nat Commun 2023; 14:3691. [PMID: 37344472 DOI: 10.1038/s41467-023-39360-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023] Open
Abstract
Polarons are entities of excess electrons dressed with local response of lattices, whose atomic-scale characterization is essential for understanding the many body physics arising from the electron-lattice entanglement, yet difficult to achieve. Here, using scanning tunneling microscopy and spectroscopy (STM/STS), we show the visualization and manipulation of single polarons in monolayer CoCl2, that are grown on HOPG substrate via molecular beam epitaxy. Two types of polarons are identified, both inducing upward local band bending, but exhibiting distinct appearances, lattice occupations and polaronic states. First principles calculations unveil origin of polarons that are stabilized by cooperative electron-electron and electron-phonon interactions. Both types of polarons can be created, moved, erased, and moreover interconverted individually by the STM tip, as driven by tip electric field and inelastic electron tunneling effect. This finding identifies the rich category of polarons in CoCl2 and their feasibility of precise control unprecedently, which can be generalized to other transition metal halides.
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Affiliation(s)
- Min Cai
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Mao-Peng Miao
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Yunfan Liang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Zeyu Jiang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Zhen-Yu Liu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Wen-Hao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Xin Liao
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Lan-Fang Zhu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Damien West
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Shengbai Zhang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, 430074, Wuhan, China.
- Wuhan Institute of Quantum Technology, 430206, Wuhan, China.
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11
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Xu T, Ichiki Y, Masuda K, Wang Y, Hirakata H, Shimada T. Ultrasmall Polar Skyrmions and Merons in SrTiO 3 Heterostructures by Polaron Engineering. ACS NANO 2023. [PMID: 37256728 DOI: 10.1021/acsnano.3c02481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Topological objects with skyrmionic textures in ferroelectrics, i.e., polar skyrmions, are promising technological paradigms in next-generation electronic devices. While breakthrough discoveries of stable polar skyrmions approximately ten nanometers in size have been very recently witnessed in complex systems, such a nontrivial topological order in ferroelectrics inevitably disappears below the ferroelectric critical size of several nanometers. Herein, we propose a strategy to overcome this limitation and achieve ultrasmall and isolated polar skyrmions by engineering excess-electron polarons in otherwise nonferroelectric SrTiO3 heterostructures. Our first-principle calculations demonstrate that a polaron localized at a SrTiO3 surface induces a Neel-type polar skyrmion as small as 1.8 nanometers attributed to the effect of atomic-scale surface roughness. Furthermore, we show that this polar topological structure is tunable by the choice of heterostructures and by the mechanical approach, which undergoes a phase transition to a meron state in the twisted boundary and to an antiskyrmion state in the surface with external shear strain, respectively. Such ultraminiaturization of skyrmions and their transitions unexpectedly unravels the formula of ultrasmall topological orders originating from the interplay between an electron polaron and structural symmetry breaking, which is completely different from the common mechanism of geometric confinement for larger-scale skyrmions. Our results not only provide a mechanism for the exploration of polar skyrmions and their rich topological transitions but also hold potential for ultrahigh-density memories.
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Affiliation(s)
- Tao Xu
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yuuki Ichiki
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Kairi Masuda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yu Wang
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Hiroyuki Hirakata
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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12
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Xiang M, Ma X, Gao C, Guo Z, Huang C, Xing Y, Tan S, Zhao J, Wang B, Shao X. Revealing the Polaron State at the MoS 2/TiO 2 Interface. J Phys Chem Lett 2023; 14:3360-3367. [PMID: 36995045 DOI: 10.1021/acs.jpclett.2c03856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Interfacial polarons determine the distribution of free charges at the interface and thus play important roles in manipulating the physicochemical properties of hybridized polaronic materials. In this work, we investigated the electronic structures at the atomically flat interface of the single-layer MoS2 (SL-MoS2) on the rutile TiO2 surface using high-resolution angle-resolved photoemission spectroscopy. Our experiments directly visualized both the valence band maximum and the conduction band minimum (CBM) of SL-MoS2 at the K point, which clearly defines a direct bandgap of ∼2.0 eV. Detailed analyses corroborated by density functional theory calculations demonstrated that the CBM of MoS2 is formed by the trapped electrons at the MoS2/TiO2 interface that couple with the longitudinal optical phonons in the TiO2 substrate through an interfacial Fröhlich polaron state. Such an interfacial coupling effect may register a new route for tuning the free charges in the hybridized systems of two-dimensional materials and functional metal oxides.
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13
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Shen S, Jiang X, Zheng Y, Xue XX, Feng Y, Zeng J, Chen KQ. Fast carrier diffusion via synergistic effects between lithium-ions and polarons in rutile TiO 2. Phys Chem Chem Phys 2023; 25:7519-7526. [PMID: 36853620 DOI: 10.1039/d2cp06058b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Carrier mobility in titanium dioxide (TiO2) systems is a key factor for their application as energy materials, especially in solar cells and lithium-ion batteries. Studies on the diffusion of Li-ions and polarons in rutile TiO2 systems have attracted extensive attention. However, how their interaction affects the diffusion of Li-ions and electron polarons is largely unclear and related studies are relatively lacking. By using first-principles calculations, we systematically investigate the interaction between the intercalated Li-ions and electron polarons in rutile TiO2 materials. Our analysis shows that the diffusion barrier of the electron polarons decreases around the Li-ion. The interaction between the Li-ions and polarons would benefit their synergistic diffusion both in the pristine and defective rutile TiO2 systems. Our study reveals the synergistic effects between the ions and polarons, which is important for understanding the carrier properties in TiO2 systems and in further improving the performance of energy materials.
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Affiliation(s)
- Shiyu Shen
- Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics & Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Xingxing Jiang
- Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics & Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Yueshao Zheng
- Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics & Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Xiong-Xiong Xue
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China
| | - Yexin Feng
- Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics & Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Jiang Zeng
- Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics & Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Ke-Qiu Chen
- Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics & Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
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14
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Fu Z, Onishi H. Infrared and Near-Infrared Spectrometry of Anatase and Rutile Particles Bandgap Excited in Liquid. J Phys Chem B 2023; 127:321-327. [PMID: 36542796 PMCID: PMC9841978 DOI: 10.1021/acs.jpcb.2c07433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/02/2022] [Indexed: 12/24/2022]
Abstract
Chemical conversion of materials is completed in milliseconds or seconds by assembling atoms over semiconductor photocatalysts. Bandgap-excited electrons and holes reactive on this time scale are key to efficient atom assembly to yield the desired products. In this study, attenuated total reflection of infrared and near-infrared light was applied to characterize and quantify the electronic absorption of TiO2 photocatalysts excited in liquid. Nanoparticles of rutile or anatase were placed on a diamond prism, covered with liquid, and irradiated by steady UV light through the prism. Electrons excited in rutile particles (JRC-TIO-6) formed small polarons characterized by a symmetric absorption band spread over 10000-700 cm-1 with a maximum at 6000 cm-1. Electrons in anatase particles (JRC-TIO-7) created large polarons and produced an asymmetric absorption band that gradually strengthened at wavenumbers below 5000 cm-1 and sharply weakened at 1000 cm-1. The absorption spectrum of large electron polarons in TIO-7 was compared with the absorption reported in a Sr-doped NaTaO3 photocatalyst, and it was suggested that excited electrons were accommodated as large polarons in NaTaO3 photocatalysts efficient for artificial photosynthesis. UV-light power dependence of the absorption bands was observed in N2-exposed decane liquid to deduce electron-hole recombination kinetics. With light power density P > 200 W m-2 (TIO-6) and 2000 W m-2 (TIO-7), the polaron absorptions were enhanced with absorbance being proportional to P1/2. The observed 1/2-order power law suggested recombination of multiple electrons and holes randomly moving in each particle. Upon excitation with smaller P, the power-law order increased to unity. The unity-order power law was interpreted with recombination of an electron and a hole that were excited by the same photon. In addition, an average lifetime of 1 ms was estimated with electron polarons in TIO-6 when weakly excited at P = 20 W m-2 to simulate solar-light irradiation.
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Affiliation(s)
- Zhebin Fu
- Department
of Chemistry, School of Science, Kobe University, Kobe, Hyogo657-8501, Japan
| | - Hiroshi Onishi
- Department
of Chemistry, School of Science, Kobe University, Kobe, Hyogo657-8501, Japan
- Research
Center for Membrane and Film Technology, Kobe University, Kobe, Hyogo657-8501, Japan
- Division
of Advanced Molecular Science, Institute
for Molecular Science, Okazaki, Aichi444-8585, Japan
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15
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Lafuente-Bartolome J, Lian C, Sio WH, Gurtubay IG, Eiguren A, Giustino F. Unified Approach to Polarons and Phonon-Induced Band Structure Renormalization. PHYSICAL REVIEW LETTERS 2022; 129:076402. [PMID: 36018689 DOI: 10.1103/physrevlett.129.076402] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Ab initio calculations of the phonon-induced band structure renormalization are currently based on the perturbative Allen-Heine theory and its many-body generalizations. These approaches are unsuitable to describe materials where electrons form localized polarons. Here, we develop a self-consistent, many-body Green's function theory of band structure renormalization that incorporates localization and self-trapping. We show that the present approach reduces to the Allen-Heine theory in the weak-coupling limit, and to total energy calculations of self-trapped polarons in the strong-coupling limit. To demonstrate this methodology, we reproduce the path-integral results of Feynman and diagrammatic Monte Carlo calculations for the Fröhlich model at all couplings, and we calculate the zero point renormalization of the band gap of an ionic insulator including polaronic effects.
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Affiliation(s)
- Jon Lafuente-Bartolome
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Chao Lian
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Weng Hong Sio
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR 999078, People's Republic of China
| | - Idoia G Gurtubay
- Fisika Saila, University of the Basque Country UPV/EHU, 48080 Bilbao, Basque Country, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country UPV/EHU, Barrio Sarriena, s/n, 48940 Leioa, Biscay, Spain
| | - Asier Eiguren
- Fisika Saila, University of the Basque Country UPV/EHU, 48080 Bilbao, Basque Country, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- EHU Quantum Center, University of the Basque Country UPV/EHU, Barrio Sarriena, s/n, 48940 Leioa, Biscay, Spain
| | - Feliciano Giustino
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
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16
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Wang YC, Zhao Y. Diagrammatic quantum Monte Carlo toward the calculation of transport properties in disordered semiconductors. J Chem Phys 2022; 156:204116. [DOI: 10.1063/5.0091124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new diagrammatic quantum Monte Carlo approach is proposed to deal with the imaginary time propagator involving both dynamic disorder (i.e., electron–phonon interactions) and static disorder of local or nonlocal nature in a unified and numerically exact way. The establishment of the whole framework relies on a general reciprocal-space expression and a generalized Wick’s theorem for the static disorder. Since the numerical cost is independent of the system size, various physical quantities, such as the thermally averaged coherence, Matsubara one-particle Green’s function, and current autocorrelation function, can be efficiently evaluated in the thermodynamic limit (infinite in the system size). The validity and performance of the proposed approach are systematically examined in a broad parameter regime. This approach, combined with proper numerical analytic continuation methods and first-principles calculations, is expected to be a versatile tool toward the calculation of various transport properties, such as mobilities in realistic semiconductors involving multiple electronic energy bands, high-frequency optical and low-frequency acoustic phonons, different forms of dynamic and static disorders, and anisotropy.
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Affiliation(s)
- Yu-Chen Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iCHEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Yi Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iCHEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
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17
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de Abreu JC, Nery JP, Giantomassi M, Gonze X, Verstraete MJ. Spectroscopic signatures of nonpolarons: the case of diamond. Phys Chem Chem Phys 2022; 24:12580-12591. [PMID: 35579374 DOI: 10.1039/d2cp01012g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polarons are quasi-particles made from electrons interacting with vibrations in crystal lattices. They derive their name from the strong electron-vibration polar interactions in ionic systems, that induce spectroscopic and optical signatures of such quasi-particles. In this paper, we focus on diamond, a non-polar crystal with inversion symmetry which nevertheless shows interesting signatures stemming from electron-vibration interactions, better denoted "nonpolaron" signatures in this case. The (non)polaronic effects are produced by short-range crystal fields, while long-range quadrupoles only have a small influence. The corresponding many-body spectral function has a characteristic energy dependence, showing a plateau structure that is similar to but distinct from the satellites observed in the polar Fröhlich case. We determine the temperature-dependent spectral function of diamond by two methods: the standard Dyson-Migdal approach, which calculates electron-phonon interactions within the lowest-order expansion of the self-energy, and the cumulant expansion, which includes higher orders of electron-phonon interactions. The latter corrects the nonpolaron energies and broadening, providing a more realistic spectral function, which we examine in detail for both conduction and valence band edges.
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Affiliation(s)
- Joao C de Abreu
- nanomat/Q-MAT/CESAM and European Theoretical Spectroscopy Facility, Université de Liège, B-4000, Belgium.
| | - Jean Paul Nery
- Dipartimento di Fisica, Università di Roma La Sapienza, I-00185 Roma, Italy
| | - Matteo Giantomassi
- UCLouvain, Institute of Condensed Matter and Nanosciences (IMCN), Chemin des Étoiles 8, B-1348 Louvain-la-Neuve, Belgium
| | - Xavier Gonze
- UCLouvain, Institute of Condensed Matter and Nanosciences (IMCN), Chemin des Étoiles 8, B-1348 Louvain-la-Neuve, Belgium.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Matthieu J Verstraete
- nanomat/Q-MAT/CESAM and European Theoretical Spectroscopy Facility, Université de Liège, B-4000, Belgium.
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18
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Direct and real-time observation of hole transport dynamics in anatase TiO2 using X-ray free-electron laser. Nat Commun 2022; 13:2531. [PMID: 35534509 PMCID: PMC9085873 DOI: 10.1038/s41467-022-30336-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 04/26/2022] [Indexed: 12/03/2022] Open
Abstract
Carrier dynamics affects photocatalytic systems, but direct and real-time observations in an element-specific and energy-level-specific manner are challenging. In this study, we demonstrate that the dynamics of photo-generated holes in metal oxides can be directly probed by using femtosecond X-ray absorption spectroscopy at an X-ray free-electron laser. We identify the energy level and life time of holes with a long life time (230 pico-seconds) in nano-crystal materials. We also observe that trapped holes show an energy distribution in the bandgap region with a formation time of 0.3 pico-seconds and a decay time of 8.0 pico-seconds at room temperature. We corroborate the dynamics of the electrons by using X-ray absorption spectroscopy at the metal L-edges in a consistent explanation with that of the holes. Direct and real-time observation of the excess holes in an element-specific and energylevel-specific manner is a challenging task. Here the authors present a complete hole dynamics of photo-excited anatase TiO2 with 100 femto-second resolution.
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19
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Troglia A, Bigi C, Vobornik I, Fujii J, Knez D, Ciancio R, Dražić G, Fuchs M, Sante DD, Sangiovanni G, Rossi G, Orgiani P, Panaccione G. Evidence of a 2D Electron Gas in a Single-Unit-Cell of Anatase TiO 2 (001). ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105114. [PMID: 35384406 PMCID: PMC9165519 DOI: 10.1002/advs.202105114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/18/2022] [Indexed: 06/14/2023]
Abstract
The formation and the evolution of electronic metallic states localized at the surface, commonly termed 2D electron gas (2DEG), represents a peculiar phenomenon occurring at the surface and interface of many transition metal oxides (TMO). Among TMO, titanium dioxide (TiO2 ), particularly in its anatase polymorph, stands as a prototypical system for the development of novel applications related to renewable energy, devices and sensors, where understanding the carrier dynamics is of utmost importance. In this study, angle-resolved photo-electron spectroscopy (ARPES) and X-ray absorption spectroscopy (XAS) are used, supported by density functional theory (DFT), to follow the formation and the evolution of the 2DEG in TiO2 thin films. Unlike other TMO systems, it is revealed that, once the anatase fingerprint is present, the 2DEG in TiO2 is robust and stable down to a single-unit-cell, and that the electron filling of the 2DEG increases with thickness and eventually saturates. These results prove that no critical thickness triggers the occurrence of the 2DEG in anatase TiO2 and give insight in formation mechanism of electronic states at the surface of TMO.
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Affiliation(s)
- Alessandro Troglia
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
- Dipartimento di FisicaUniversitá di MilanoVia Celoria 16Milano20133Italy
| | - Chiara Bigi
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
- Dipartimento di FisicaUniversitá di MilanoVia Celoria 16Milano20133Italy
| | - Ivana Vobornik
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
| | - Jun Fujii
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
| | - Daniel Knez
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
| | - Regina Ciancio
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
| | - Goran Dražić
- Department of Materials ChemistryNational Institute of ChemistryHajdrihova 19Ljubljana1001Slovenia
| | - Marius Fuchs
- Institut für Theoretische Physik und Astrophysik and Würzburg‐Dresden Cluster of Excellence ct.qmatUniversität WürzburgWürzburg97074Germany
| | - Domenico Di Sante
- Department of Physics and AstronomyUniversity of BolognaBologna40127Italy
- Center for Computational Quantum PhysicsFlatiron Institute162 5th AvenueNew YorkNY10010USA
| | - Giorgio Sangiovanni
- Institut für Theoretische Physik und Astrophysik and Würzburg‐Dresden Cluster of Excellence ct.qmatUniversität WürzburgWürzburg97074Germany
| | - Giorgio Rossi
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
- Dipartimento di FisicaUniversitá di MilanoVia Celoria 16Milano20133Italy
| | - Pasquale Orgiani
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)‐CNRLaboratorio TASC in Area Science Park, S.S. 14 Km 163.5Trieste34149Italy
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20
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Sajedi M, Krivenkov M, Marchenko D, Sánchez-Barriga J, Chandran AK, Varykhalov A, Rienks EDL, Aguilera I, Blügel S, Rader O. Is There a Polaron Signature in Angle-Resolved Photoemission of CsPbBr_{3}? PHYSICAL REVIEW LETTERS 2022; 128:176405. [PMID: 35570464 DOI: 10.1103/physrevlett.128.176405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 11/19/2021] [Accepted: 03/17/2022] [Indexed: 06/15/2023]
Abstract
The formation of large polarons has been proposed as reason for the high defect tolerance, low mobility, low charge carrier trapping, and low nonradiative recombination rates of lead halide perovskites. Recently, direct evidence for large-polaron formation has been reported from a 50% effective mass enhancement in angle-resolved photoemission of CsPbBr_{3} over theory for the orthorhombic structure. We present in-depth band dispersion measurements of CsPbBr_{3} and GW calculations, which lead to similar effective masses at the valence band maximum of 0.203±0.016 m_{0} in experiment and 0.226 m_{0} in orthorhombic theory. We argue that the effective mass can be explained solely on the basis of electron-electron correlation and large-polaron formation cannot be concluded from photoemission data.
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Affiliation(s)
- Maryam Sajedi
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam, Germany
| | - Maxim Krivenkov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Dmitry Marchenko
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Jaime Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Anoop K Chandran
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, 52056 Aachen, Germany
| | - Andrei Varykhalov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Emile D L Rienks
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Irene Aguilera
- Institute of Energy and Climate Research, IEK-5 Photovoltaics, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Stefan Blügel
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Oliver Rader
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
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21
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Zhao J, Mu X, Wang L, Fang Z, Zou X, Cao J. Homogeneously Large Polarons in Aromatic Passivators Improves Charge Transport between Perovskite Grains for >24 % Efficiency in Photovoltaics. Angew Chem Int Ed Engl 2022; 61:e202116308. [DOI: 10.1002/anie.202116308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Indexed: 11/07/2022]
Affiliation(s)
- Jia‐Hui Zhao
- State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P.R. China
| | - Xijiao Mu
- State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P.R. China
| | - Luyao Wang
- State School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P.R. China
| | - Zihan Fang
- State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P.R. China
| | - Xiaoxin Zou
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P.R. China
| | - Jing Cao
- State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P.R. China
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22
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Dong S, Xia S, Wang C, Dong J, Wang T, Li R, Ren Z, Dai D, Yang X, Zhou C. Valence Band of Rutile TiO 2(110) Investigated by Polarized-Light-Based Angle-Resolved Photoelectron Spectroscopy. J Phys Chem Lett 2022; 13:2299-2305. [PMID: 35244399 DOI: 10.1021/acs.jpclett.2c00142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Band structure dictates optical and electronic properties of solids and eventually the efficiency of the semiconductor based solar conversion. Compared to numerous theoretical calculations, the experimentally measured band structure of rutile TiO2, a prototypical photocatalytic material, is rare. In this work, the valence band structure of rutile TiO2(110) is measured by angle-resolved photoelectron spectroscopy using polarized extreme ultraviolet light. The effective mass of the hole, which has never been measured before, is determined to be 4.66-6.87 m0 (free electron mass) and anisotropic. The dependence of photoemission intensities on excitation light polarization is analyzed by taking into account of the parity symmetry of molecular orbitals in the blocking unit of rutile TiO2. This work reports a direct measurement of valence band structure and hole effective mass of rutile TiO2(110), which will deepen our understanding of the electronic structure and charge carrier properties of the model material and provide reference data for future theoretical calculations.
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Affiliation(s)
- Shanshan Dong
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, 100049, Beijing, P. R. China
| | - Shucai Xia
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, 100049, Beijing, P. R. China
| | - Chao Wang
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Ganjingzi District, Dalian, 116024, Liaoning, P. R. China
| | - Jingwei Dong
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
| | - Tianjun Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
| | - Rui Li
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Ganjingzi District, Dalian, 116024, Liaoning, P. R. China
| | - Zefeng Ren
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
| | - Dongxu Dai
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
- Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong, 518055, P. R. China
| | - Chuanyao Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, Liaoning, P. R. China
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23
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Zhang L, Chu W, Zheng Q, Zhao J. Effects of oxygen vacancies on the photoexcited carrier lifetime in rutile TiO 2. Phys Chem Chem Phys 2022; 24:4743-4750. [PMID: 35142307 DOI: 10.1039/d1cp04248c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoexcited carrier lifetime in semiconductors plays a crucial role in solar energy conversion processes. The defects or impurities in semiconductors are usually proposed to introduce electron-hole (e-h) recombination centers and consequently reduce the photoexcited carrier lifetime. In this report, we investigate the effects of oxygen vacancies (OV) on the carrier lifetime in rutile TiO2, which has important applications in photocatalysis and photovoltaics. It is found that an OV introduces two excess electrons which form two defect states in the band gap. The lower state is localized on one Ti atom and behaves as a small polaron, and the higher one is a hybrid state contributed by three Ti atoms around the OV. Both the polaron and hybrid states exhibit strong electron-phonon (e-ph) coupling and their charge distributions become more and more delocalized when the temperature increases from 100 to 700 K. Such strong e-ph coupling and charge delocalization enhance the nonadibatic coupling between the electronic states along the hole relaxation path, where the defect states behave as intermediate states, leading to a distinct acceleration of e-h recombination. Our study provides valuable insights to understand the role of defects on photoexcited carrier lifetime in semiconductors.
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Affiliation(s)
- Lili Zhang
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. .,Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Weibin Chu
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. .,Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
| | - Qijing Zheng
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Jin Zhao
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
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24
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HAADF STEM and Ab Initio Calculations Investigation of Anatase TiO2/LaAlO3 Heterointerface. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The understanding of the origin of a two-dimensional electron gas (2DEG) at the surface of anatase TiO2 remains a challenging issue. In particular, in TiO2 ultra-thin films, it is extremely difficult to distinguish intrinsic effects, due to the physics of the TiO2, from extrinsic effects, such as those arising from structural defects, dislocations, and the presence of competing phases at the film/substrate interface. It is, therefore, mandatory to unambiguously ascertain the structure of the TiO2/substrate interface. In this work, by combining high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), density functional theory calculations, and multislice image simulations, we have investigated the nature of strainless anatase TiO2 thin films grown on LaAlO3 substrate. In particular, the presence of oxygen vacancies in anatase TiO2 has been proved to stabilize the formation of an extra alloy layer, Ti2AlO4, by means of interface rearrangement. Our results, therefore, elucidate why the growth of anatase TiO2 directly on LaAlO3 substrate has required the deposition of a TiOx extra-layer to have a 2DEG established, thus confirming the absence of a critical thickness for the TiO2 to stabilize a 2DEG at its surface. These findings provide fundamental insights on the underlying formation mechanism of the 2DEG in TiO2/LAO hetero-interfaces to engineer the 2DEG formation in anatase TiO2 for tailored applications.
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25
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Tanner AJ, Thornton G. TiO 2 Polarons in the Time Domain: Implications for Photocatalysis. J Phys Chem Lett 2022; 13:559-566. [PMID: 35014263 PMCID: PMC9097515 DOI: 10.1021/acs.jpclett.1c03677] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Exploiting the availability of solar energy to produce valuable chemicals is imperative in our quest for a sustainable energy cycle. TiO2 has emerged as an efficient photocatalyst, and as such its photochemistry has been studied extensively. It is well-known that polaronic defect states impact the activity of this chemistry. As such, understanding the fundamental excitation mechanisms deserves the attention of the scientific community. However, isolating the contribution of polarons to these processes has required increasingly creative experimental techniques and expensive theory. In this Perspective, we discuss recent advances in this field, with a particular focus on two-photon photoemission spectroscopy (2PPE) and density functional theory (DFT), and discuss the implications for photocatalysis.
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26
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Zhao JH, Mu X, Wang L, Fang Z, Zou X, Cao J. Homogeneously Large Polarons in Aromatic Passivators Improves Charge Transport Between Perovskite Grains for >24% Efficiency in Photovoltaics. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jia-Hui Zhao
- Lanzhou University College of Chemistry and Chemical Engineering CHINA
| | - Xijiao Mu
- Lanzhou University College of Chemistry and Chemical Engineering CHINA
| | - Luyao Wang
- Shanghai Jiaotong University: Shanghai Jiao Tong University School of Materials Science and Engineering CHINA
| | - Zihan Fang
- Lanzhou University College of Chemistry and Chemical Engineering CHINA
| | | | - Jing Cao
- Lanzhou University College of chemistry and chemical engineering Lanzhou CHINA
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27
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Photo-induced ultrafast electron dynamics in anatase and rutile TiO 2: Effects of the electron-phonon interaction. CHINESE J CHEM PHYS 2022. [DOI: 10.1063/1674-0068/cjcp2111264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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28
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Abstract
Recent studies have demonstrated that higher than two-body bath-impurity correlations are not important for quantitatively describing the ground state of the Bose polaron. Motivated by the above, we employ the so-called Gross Ansatz (GA) approach to unravel the stationary and dynamical properties of the homogeneous one-dimensional Bose-polaron for different impurity momenta and bath-impurity couplings. We explicate that the character of the equilibrium state crossovers from the quasi-particle Bose polaron regime to the collective-excitation stationary dark-bright soliton for varying impurity momentum and interactions. Following an interspecies interaction quench the temporal orthogonality catastrophe is identified, provided that bath-impurity interactions are sufficiently stronger than the intraspecies bath ones, thus generalizing the results of the confined case. This catastrophe originates from the formation of dispersive shock wave structures associated with the zero-range character of the bath-impurity potential. For initially moving impurities, a momentum transfer process from the impurity to the dispersive shock waves via the exerted drag force is demonstrated, resulting in a final polaronic state with reduced velocity. Our results clearly demonstrate the crucial role of non-linear excitations for determining the behavior of the one-dimensional Bose polaron.
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29
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De Lile JR, Bahadoran A, Zhou S, Zhang J. Polaron in TiO
2
from First‐Principles: A Review. ADVANCED THEORY AND SIMULATIONS 2021. [DOI: 10.1002/adts.202100244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Jeffrey Roshan De Lile
- Department of physical engineering Polytechnique Montréal Case postal 6079, Station Centre‐ville Montréal Québec H3C 3A7 Canada
- Department of Physics and Regroupement québécois sur les matériaux de pointe Université de Montréal 1375 Ave.Thérèse‐Lavoie‐Roux Montréal QC H2V 0B3 Canada
| | - Ashkan Bahadoran
- State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Su Zhou
- School of Automotive Studies Tongji University Cao'an road Shanghai 201804 P. R. China
| | - Jiujun Zhang
- Institute of Sustainable Energy/College of Sciences Shanghai University Shanghai 200444 P. R. China
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30
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Guedes EB, Muff S, Brito WH, Caputo M, Li H, Plumb NC, Dil JH, Radović M. Universal Structural Influence on the 2D Electron Gas at SrTiO 3 Surfaces. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100602. [PMID: 34532983 PMCID: PMC8596100 DOI: 10.1002/advs.202100602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/23/2021] [Indexed: 05/28/2023]
Abstract
The 2-dimensional electron gas (2DEG) found at the surface of SrTiO3 and related interfaces has attracted significant attention as a promising basis for oxide electronics. In order to utilize its full potential, the response of this 2DEG to structural changes and surface modification must be understood in detail. Here, a study of the detailed electronic structure evolution of the 2DEG as a function of sample temperature and surface step density is presented. By comparing the experimental results with ab initio calculations, it is shown that local structure relaxations cause a metal-insulator transition of the system around 135 K. This study presents a new and simple way of tuning the 2DEG via surface vicinality and identifies how the operation of prospective devices will respond to changes in temperature.
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Affiliation(s)
- Eduardo B. Guedes
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
| | - Stefan Muff
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
| | - Walber H. Brito
- Departamento de FísicaUniversidade Federal de Minas GeraisC.P. 702Belo HorizonteMinas Gerais30123Brazil
| | - Marco Caputo
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
- Elettra‐Sincrotrone TriesteS.C.p.A, S.S 14‐km 163.5 in AREA Science Park, BasovizzaTrieste34149Italy
| | - Hang Li
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
- Department of Energy Conversion and StorageTechnical University of DenmarkKgs. Lyngby2800Denmark
| | - Nicholas C. Plumb
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
| | - J. Hugo Dil
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
- Institut de PhysiqueÉcole Polytechnique Fédérale de LausanneLausanneCH‐1015Switzerland
| | - Milan Radović
- Photon Science DivisionPaul Scherrer InstitutVilligenCH‐5232Switzerland
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31
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Kang L, Du X, Zhou JS, Gu X, Chen YJ, Xu RZ, Zhang QQ, Sun SC, Yin ZX, Li YW, Pei D, Zhang J, Gu RK, Wang ZG, Liu ZK, Xiong R, Shi J, Zhang Y, Chen YL, Yang LX. Band-selective Holstein polaron in Luttinger liquid material A 0.3MoO 3 (A = K, Rb). Nat Commun 2021; 12:6183. [PMID: 34702828 PMCID: PMC8548323 DOI: 10.1038/s41467-021-26078-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/14/2021] [Indexed: 11/09/2022] Open
Abstract
(Quasi-)one-dimensional systems exhibit various fascinating properties such as Luttinger liquid behavior, Peierls transition, novel topological phases, and the accommodation of unique quasiparticles (e.g., spinon, holon, and soliton, etc.). Here we study molybdenum blue bronze A0.3MoO3 (A = K, Rb), a canonical quasi-one-dimensional charge-density-wave material, using laser-based angle-resolved photoemission spectroscopy. Our experiment suggests that the normal phase of A0.3MoO3 is a prototypical Luttinger liquid, from which the charge-density-wave emerges with decreasing temperature. Prominently, we observe strong renormalizations of band dispersions, which are recognized as the spectral function of Holstein polaron derived from band-selective electron-phonon coupling in the system. We argue that the strong electron-phonon coupling plays an important role in electronic properties and the charge-density-wave transition in blue bronzes. Our results not only reconcile the long-standing heavy debates on the electronic properties of blue bronzes but also provide a rare platform to study interesting excitations in Luttinger liquid materials.
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Affiliation(s)
- L Kang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - X Du
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - J S Zhou
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - X Gu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Y J Chen
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - R Z Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Q Q Zhang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - S C Sun
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Z X Yin
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Y W Li
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China.,ShanghaiTech Laboratory for Topological Physics, Shanghai, 200031, China
| | - D Pei
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, UK
| | - J Zhang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China
| | - R K Gu
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, UK
| | - Z G Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Z K Liu
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China.,ShanghaiTech Laboratory for Topological Physics, Shanghai, 200031, China
| | - R Xiong
- Department of Physics, Wuhan University, Wuhan, 430072, China
| | - J Shi
- Department of Physics, Wuhan University, Wuhan, 430072, China
| | - Y Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Y L Chen
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China. .,School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China. .,ShanghaiTech Laboratory for Topological Physics, Shanghai, 200031, China. .,Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, UK.
| | - L X Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China. .,Frontier Science Center for Quantum Information, Beijing, 100084, China.
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32
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Schubert JS, Kalantari L, Lechner A, Giesriegl A, Nandan SP, Alaya P, Kashiwaya S, Sauer M, Foelske A, Rosen J, Blaha P, Cherevan A, Eder D. Elucidating the formation and active state of Cu co-catalysts for photocatalytic hydrogen evolution. JOURNAL OF MATERIALS CHEMISTRY. A 2021; 9:21958-21971. [PMID: 34707872 PMCID: PMC8492008 DOI: 10.1039/d1ta05561e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
The design of active and selective co-catalysts constitutes one of the major challenges in developing heterogeneous photocatalysts for energy conversion applications. This work provides a comprehensive insight into thermally induced bottom-up generation and transformation of a series of promising Cu-based co-catalysts. We demonstrate that the volcano-type HER profile as a function of calcination temperature is independent of the type of the Cu precursor but is affected by changes in oxidation state and location of the copper species. Supported by DFT modeling, our data suggest that low temperature (<200 °C) treatments facilitate electronic communication between the Cu species and TiO2, which allows for a more efficient charge utilization and maximum HER rates. In contrast, higher temperatures (>200 °C) do not affect the Cu oxidation state, but induce a gradual, temperature-dependent surface-to-bulk diffusion of Cu, which results in interstitial, tetra-coordinated Cu+ species. The disappearance of Cu from the surface and the introduction of new defect states is associated with a drop in HER performance. This work examines electronic and structural effects that are in control of the photocatalytic activity and can be transferred to other systems for further advancing photocatalysis.
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Affiliation(s)
- Jasmin S Schubert
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Leila Kalantari
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Andreas Lechner
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Ariane Giesriegl
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Sreejith P Nandan
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Pablo Alaya
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Shun Kashiwaya
- Materials Design, Department of Physics, Chemistry, and Biology (IFM), Linköping University 58183 Linköping Sweden
| | - Markus Sauer
- Analytical Instrumentation Center, Technische Universität Wien (TU Wien) Lehargasse 6 1060 Vienna Austria
| | - Annette Foelske
- Analytical Instrumentation Center, Technische Universität Wien (TU Wien) Lehargasse 6 1060 Vienna Austria
| | - Johanna Rosen
- Materials Design, Department of Physics, Chemistry, and Biology (IFM), Linköping University 58183 Linköping Sweden
| | - Peter Blaha
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Alexey Cherevan
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
| | - Dominik Eder
- Institute of Materials Chemistry, Technische Universität Wien (TU Wien) Getreidemarkt 9 1060 Vienna Austria
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33
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Wang YC, Jiang H. Constrained density functional theory plus the Hubbard U correction approach for the electronic polaron mobility: A case study of TiO2. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2108136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Yue-Chao Wang
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Hong Jiang
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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34
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Guo P, Fu X, Deák P, Frauenheim T, Xiao J. Activity and Mechanism Mapping of Photocatalytic NO 2 Conversion on the Anatase TiO 2(101) Surface. J Phys Chem Lett 2021; 12:7708-7716. [PMID: 34355897 DOI: 10.1021/acs.jpclett.1c02263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
NOx emission heavily affects our environment and human health. Photocatalytic denitrification (deNOx) attracted much attention because it is low-cost and nonpolluting, but undesired nitrite and nitrate were produced in reality, instead of harmless N2. Unveiling the active sites and the photocatalytic mechanism is very important to improve the process. Herein, we have employed a combinational scenario to investigate the reaction mechanism of NO2 and H2O on anatase TiO2(101). On the one hand, a polaron-corrected GGA functional (GGA + Lany-Zunger) was applied to improve the description of electronic states in photoassisted processes. On the other hand, a reaction phase diagram (RPD) was established to understand the (quasi) activity trend over both perfect and defective surfaces. It was found that a perfect surface is more active via the Eley-Rideal mechanism without NO2 adsorption, while the activity on defective surfaces is limited by the sluggish recombinative desorption. A photogenerated hole can weaken the OH* adsorption energies and circumvents the scaling relation of the dark reaction, eventually enhancing the deNOx activity significantly. The insights gained from our work indicate that tuning the reactivity by illumination-induced localized charge and diverse reaction pathways are two methods for improving adsorption, dissociation, and desorption processes to go beyond the conventional activity volcano plot limit of dark conditions.
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Affiliation(s)
- Pu Guo
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
| | - Xiaoyan Fu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Peter Deák
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany
- Computational Science Research Center, No. 10 East Xibeiwang Road, Beijing 100193, China
- Computational Science and Applied Research Institute (CSAR), Shenzhen 518110, China
| | - Jianping Xiao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
- Dalian National Laboratory for Clean Energy, Dalian 116023, P.R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
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35
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High-order replica bands in monolayer FeSe/SrTiO 3 revealed by polarization-dependent photoemission spectroscopy. Nat Commun 2021; 12:4573. [PMID: 34321473 PMCID: PMC8319137 DOI: 10.1038/s41467-021-24783-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 07/09/2021] [Indexed: 11/13/2022] Open
Abstract
The mechanism of the enhanced superconductivity in monolayer FeSe/SrTiO3 has been enthusiastically studied and debated over the past decade. One specific observation has been taken to be of central importance: the replica bands in the photoemission spectrum. Although suggestive of electron-phonon interaction in the material, the essence of these spectroscopic features remains highly controversial. In this work, we conduct angle-resolved photoemission spectroscopy measurements on monolayer FeSe/SrTiO3 using linearly polarized photons. This configuration enables unambiguous characterization of the valence electronic structure with a suppression of the spectral background. We consistently observe high-order replica bands derived from various Fe 3d bands, similar to those observed on bare SrTiO3. The intensity of the replica bands is unexpectedly high and different between dxy and dyz bands. Our results provide new insights on the electronic structure of this high-temperature superconductor and the physical origin of the photoemission replica bands. The origin of the photoemission replica bands in monolayer FeSe/SrTiO3 remains controversial. Here, the authors perform angle-resolved photoemission spectroscopy with polarized photon on FeSe/SrTiO3 and observe high-order replica bands with high intensity from various Fe 3d bands, suggesting a mixed mechanism.
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36
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Faeth BD, Xie S, Yang S, Kawasaki JK, Nelson JN, Zhang S, Parzyck C, Mishra P, Li C, Jozwiak C, Bostwick A, Rotenberg E, Schlom DG, Shen KM. Interfacial Electron-Phonon Coupling Constants Extracted from Intrinsic Replica Bands in Monolayer FeSe/SrTiO_{3}. PHYSICAL REVIEW LETTERS 2021; 127:016803. [PMID: 34270322 DOI: 10.1103/physrevlett.127.016803] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/26/2021] [Accepted: 05/19/2021] [Indexed: 06/13/2023]
Abstract
The observation of replica bands by angle-resolved photoemission spectroscopy has ignited interest in the study of electron-phonon coupling at low carrier densities, particularly in monolayer FeSe/SrTiO_{3}, where the appearance of replica bands has motivated theoretical work suggesting that the interfacial coupling of electrons in the FeSe layer to optical phonons in the SrTiO_{3} substrate might contribute to the enhanced superconducting pairing temperature. Alternatively, it has also been recently proposed that such replica bands might instead originate from extrinsic final state losses associated with the photoemission process. Here, we perform a quantitative examination of replica bands in monolayer FeSe/SrTiO_{3}, where we are able to conclusively demonstrate that the replica bands are indeed signatures of intrinsic electron-boson coupling, and not associated with final state effects. A detailed analysis of the energy splittings and relative peak intensities between the higher-order replicas, as well as other self-energy effects, allows us to determine that the interfacial electron-phonon coupling in the system corresponds to a value of λ=0.19±0.02, providing valuable insights into the enhancement of superconductivity in monolayer FeSe/SrTiO_{3}. The methodology employed here can also serve as a new and general approach for making more rigorous and quantitative comparisons to theoretical calculations of electron-phonon interactions and coupling constants.
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Affiliation(s)
- Brendan D Faeth
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Saien Xie
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Shuolong Yang
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Jason K Kawasaki
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - Jocienne N Nelson
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Shuyuan Zhang
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Christopher Parzyck
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Pramita Mishra
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Chen Li
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Christopher Jozwiak
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Darrell G Schlom
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Kyle M Shen
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
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Shang H, Yang J. Capturing the Electron-Phonon Renormalization in Molecules from First-Principles. J Phys Chem A 2021; 125:2682-2689. [PMID: 33755483 DOI: 10.1021/acs.jpca.0c10897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Since the interaction between electrons and atomic nuclei can affect the electronic structure, in recent years, first-principles-based electron-phonon renormalization methods have been applied in the condensed matter physics community to account for the influence of the electron-phonon coupling in solid systems. However, little is yet known about the behavior and trends of the electron-phonon renormalization in the molecules. In this work, the method for the electron-phonon renormalization in molecules has been derived, using which, we exhaustively investigate the zero-point renormalization in 32 molecules with three different density functions. We find that the renormalization of the highest occupied molecular orbital-lowest unoccupied molecular orbital gap due to electron-vibration coupling does not relate to the atomic masses but quite relates to the electronic structure properties of the molecules.
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Affiliation(s)
- Honghui Shang
- State Key Laboratory of Computer Architecture, Institute of Computing Technology, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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38
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Liu Z, Liu W, Zhou R, Cai S, Song Y, Yao Q, Lu X, Liu J, Liu Z, Wang Z, Zheng Y, Wang P, Liu Z, Li G, Shen D. Electron-plasmon interaction induced plasmonic-polaron band replication in epitaxial perovskite SrIrO 3 films. Sci Bull (Beijing) 2021; 66:433-440. [PMID: 36654180 DOI: 10.1016/j.scib.2020.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/08/2020] [Accepted: 09/21/2020] [Indexed: 01/20/2023]
Abstract
Electron-boson interaction is fundamental to a thorough understanding of various exotic properties emerging in many-body physics. In photoemission spectroscopy, photoelectron emission due to photon absorption would trigger diverse collective excitations in solids, including the emergence of phonons, magnons, electron-hole pairs, and plasmons, which naturally provides a reliable pathway to study electron-boson couplings. While fingerprints of electron-phonon/-magnon interactions in this state-of-the-art technique have been well investigated, much less is known about electron-plasmon coupling, and direct observation of the band renormalization solely due to electron-plasmon interactions is extremely challenging. Here by utilizing integrated oxide molecular-beam epitaxy and angle-resolved photoemission spectroscopy, we discover the long sought-after pure electron-plasmon coupling-induced low-lying plasmonic-polaron replica bands in epitaxial semimetallic SrIrO3 films, in which the characteristic low carrier concentration and narrow bandwidth combine to provide a unique platform where the electron-plasmon interaction can be investigated kinematically in photoemission spectroscopy. This finding enriches the forms of electron band normalization on collective modes in solids and demonstrates that, to obtain a complete understanding of the quasiparticle dynamics in 5d electron systems, the electron-plasmon interaction should be considered on equal footing with the acknowledged electron-electron interaction and spin-orbit coupling.
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Affiliation(s)
- Zhengtai Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wanling Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China; School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruixiang Zhou
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Songhua Cai
- Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yekai Song
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China; School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qi Yao
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiangle Lu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jishan Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhonghao Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Wang
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China; Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Yi Zheng
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China; Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Peng Wang
- Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhi Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Gang Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - Dawei Shen
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
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39
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Zhang L, Chu W, Zhao C, Zheng Q, Prezhdo OV, Zhao J. Dynamics of Photoexcited Small Polarons in Transition-Metal Oxides. J Phys Chem Lett 2021; 12:2191-2198. [PMID: 33630612 DOI: 10.1021/acs.jpclett.1c00003] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The dynamics of photoexcited polarons in transition-metal oxides (TMOs), including their formation, migration, and quenching, plays an important role in photocatalysis and photovoltaics. Taking rutile TiO2 as a prototypical system, we use ab initio nonadiabatic molecular dynamics simulation to investigate the dynamics of small polarons induced by photoexcitation at different temperatures. The photoexcited electron is trapped by the distortion of the surrounding lattice and forms a small polaron within tens of femtoseconds. Polaron migration among Ti atoms is strongly correlated with quenching through an electron-hole (e-h) recombination process. At low temperature, the polaron is localized on a single Ti atom and polaron quenching occurs within several nanoseconds. At increased temperature, as under solar cell operating conditions, thermal phonon excitation stimulates the hopping and delocalization of polarons, which induces fast polaron quenching through the e-h recombination within 200 ps. Our study proves that e-h recombination centers can be formed by photoexcited polarons, which provides new insights to understand the efficiency bottleneck of photocatalysis and photovoltaics in TMOs.
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Affiliation(s)
- Lili Zhang
- Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Weibin Chu
- Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | | | | | - Oleg V Prezhdo
- Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Jin Zhao
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh Pennsylvania 15260, United States
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40
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King PDC, Picozzi S, Egdell RG, Panaccione G. Angle, Spin, and Depth Resolved Photoelectron Spectroscopy on Quantum Materials. Chem Rev 2021; 121:2816-2856. [PMID: 33346644 DOI: 10.1021/acs.chemrev.0c00616] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of X-ray based electron spectroscopies in determining chemical, electronic, and magnetic properties of solids has been well-known for several decades. A powerful approach is angle-resolved photoelectron spectroscopy, whereby the kinetic energy and angle of photoelectrons emitted from a sample surface are measured. This provides a direct measurement of the electronic band structure of crystalline solids. Moreover, it yields powerful insights into the electronic interactions at play within a material and into the control of spin, charge, and orbital degrees of freedom, central pillars of future solid state science. With strong recent focus on research of lower-dimensional materials and modified electronic behavior at surfaces and interfaces, angle-resolved photoelectron spectroscopy has become a core technique in the study of quantum materials. In this review, we provide an introduction to the technique. Through examples from several topical materials systems, including topological insulators, transition metal dichalcogenides, and transition metal oxides, we highlight the types of information which can be obtained. We show how the combination of angle, spin, time, and depth-resolved experiments are able to reveal "hidden" spectral features, connected to semiconducting, metallic and magnetic properties of solids, as well as underlining the importance of dimensional effects in quantum materials.
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Affiliation(s)
- Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche, CNR-SPIN, Via dei Vestini 31, Chieti 66100, Italy
| | - Russell G Egdell
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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41
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Ma X, Cheng Z, Tian M, Liu X, Cui X, Huang Y, Tan S, Yang J, Wang B. Formation of Plasmonic Polarons in Highly Electron-Doped Anatase TiO 2. NANO LETTERS 2021; 21:430-436. [PMID: 33290081 DOI: 10.1021/acs.nanolett.0c03802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The existence of various quasiparticles of polarons because of electron-boson couplings plays important roles in determining electron transport in titanium dioxide (TiO2), which affects a wealth of physical properties from catalysis to interfacial superconductivity. In addition to the well-defined Fröhlich polarons whose electrons are dressed by the phonon clouds, it has been theoretically predicted that electrons can also couple to their own plasmonic oscillations, namely, the plasmonic polarons. Here we experimentally demonstrate the formation of plasmonic polarons in highly doped anatase TiO2 using angle-resolved photoemission spectroscopy. Our results show that the energy separation of plasmon-loss satellites follows a dependence on √n, where n is the electron density, manifesting the characteristic of plasmonic polarons. The spectral functions enable to quantitatively evaluate the strengths of electron-plasmon and electron-phonon couplings, respectively, providing an effective approach for characterizing the interplays among different bosonic modes in the complicate many-body interactions.
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Affiliation(s)
- Xiaochuan Ma
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhengwang Cheng
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Mingyang Tian
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaofeng Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xuefeng Cui
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yaobo Huang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Shijing Tan
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bing Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China
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Observation of the polaronic character of excitons in a two-dimensional semiconducting magnet CrI 3. Nat Commun 2020; 11:4780. [PMID: 32963250 PMCID: PMC7508859 DOI: 10.1038/s41467-020-18627-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/27/2020] [Indexed: 11/16/2022] Open
Abstract
Exciton dynamics can be strongly affected by lattice vibrations through electron-phonon coupling. This is rarely explored in two-dimensional magnetic semiconductors. Focusing on bilayer CrI3, we first show the presence of strong electron-phonon coupling through temperature-dependent photoluminescence and absorption spectroscopy. We then report the observation of periodic broad modes up to the 8th order in Raman spectra, attributed to the polaronic character of excitons. We establish that this polaronic character is dominated by the coupling between the charge-transfer exciton at 1.96 eV and a longitudinal optical phonon at 120.6 cm−1. We further show that the emergence of long-range magnetic order enhances the electron-phonon coupling strength by ~50% and that the transition from layered antiferromagnetic to ferromagnetic order tunes the spectral intensity of the periodic broad modes, suggesting a strong coupling among the lattice, charge and spin in two-dimensional CrI3. Our study opens opportunities for tailoring light-matter interactions in two-dimensional magnetic semiconductors. Exciton dynamics can be strongly affected by lattice vibrations through electron-phonon (e-ph) coupling. Here, the authors show the presence of strong e-ph coupling in bilayer CrI3 and observe a Raman feature with periodic broad modes up to the 8th order, attributed to the polaronic character of excitons.
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43
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Knez D, Dražić G, Chaluvadi SK, Orgiani P, Fabris S, Panaccione G, Rossi G, Ciancio R. Unveiling Oxygen Vacancy Superstructures in Reduced Anatase Thin Films. NANO LETTERS 2020; 20:6444-6451. [PMID: 32794711 DOI: 10.1021/acs.nanolett.0c02125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Oxygen vacancies are known to play a crucial role in tuning the physical properties and technological applications of titanium dioxide TiO2. Over the last decades, defects in substoichiometric TiO2 have been commonly associated with the formation of TinO2n-x Magnéli phases, which are extended planar defects originating from crystallographic shear planes. By combining advanced transmission electron microscopy techniques, electron energy-loss spectroscopy and atomistic simulations, we reach new understanding of the oxygen vacancy induced structural modulations in anatase, ruling out the earlier shear-plane model. Structural modulations are instead shown to be due to the formation of oxygen vacancy superstructures that extend periodically inside the films, preserving the crystalline order of anatase. Elucidating the structure of oxygen defects in anatase is a crucial step for improving the functionalities of such material system and to engineer devices with targeted properties.
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Affiliation(s)
- Daniel Knez
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Goran Dražić
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
| | - Sandeep Kumar Chaluvadi
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Pasquale Orgiani
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Stefano Fabris
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - Giorgio Rossi
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
- Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - Regina Ciancio
- Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
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44
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Ultrafast dynamics of hot carriers in a quasi-two-dimensional electron gas on InSe. Proc Natl Acad Sci U S A 2020; 117:21962-21967. [PMID: 32848070 DOI: 10.1073/pnas.2008282117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two-dimensional electron gases (2DEGs) are at the base of current nanoelectronics because of their exceptional mobilities. Often the accumulation layer forms at polar interfaces with longitudinal optical (LO) modes. In most cases, the many-body screening of the quasi-2DEGs dramatically reduces the Fröhlich scattering strength. Despite the effectiveness of such a process, it has been recurrently proposed that a remote coupling with LO phonons persists even at high carrier concentration. We address this issue by perturbing electrons in an accumulation layer via an ultrafast laser pulse and monitoring their relaxation via time- and momentum-resolved spectroscopy. The cooling rate of excited carriers is monitored at doping level spanning from the semiconducting to the metallic limit. We observe that screening of LO phonons is not as efficient as it would be in a strictly 2D system. The large discrepancy is due to the remote coupling of confined states with the bulk. Our data indicate that the effect of such a remote coupling can be mimicked by a 3D Fröhlich interaction with Thomas-Fermi screening. These conclusions are very general and should apply to field effect transistors (FET) with high-κ dielectric gates, van der Waals heterostructures, and metallic interfaces between insulating oxides.
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45
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Zhu YN, Teobaldi G, Liu LM. Water-Hydrogen-Polaron Coupling at Anatase TiO 2(101) Surfaces: A Hybrid Density Functional Theory Study. J Phys Chem Lett 2020; 11:4317-4325. [PMID: 32354210 DOI: 10.1021/acs.jpclett.0c00917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Defects and water generally coexist on the surfaces of reducible metal oxides for heterogeneous photocatalysis in aqueous environments, which makes quantification and understanding of their coupling essential for development of practical solutions. Here we explore and quantify the coupling between water (H2O)- and hydrogen (H)-induced electron-polarons on the TiO2 anatase (101) surface by means of first-principles simulations. Without H2O, the hydrogen-induced electron-polaron localizes preferentially around the energetically favored subsurface H site. Its hopping barrier to neighboring sites in the subsurface is about 0.29 eV. Conversely, following H2O adsorption, surface trapping of the electron-polaron becomes energetically favored, and the diffusion barrier from subsurface to surface decreases by 0.15 eV. H2O adsorption is shown to be effective in decreasing the proton diffusion energy barrier within the same layer by reducing the polaron-proton coupling and promoting diffusion toward the subsurface in line with a recent experimental observation on water-dispersed anatase TiO2 nanoparticles.
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Affiliation(s)
- Ya-Nan Zhu
- Beijing Computational Science Research Center, Beijing 100193, China
- School of Physics, Beihang University, Beijing 100191, China
| | - Gilberto Teobaldi
- Scientific Computing Department, STFC UKRI, Rutherford Appleton Laboratory, Harwell Campus, OX11 0QX Didcot, United Kingdom
- Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, L69 3BX Liverpool, United Kingdom
- School of Chemistry, University of Southampton, Highfield, SO17 1BJ Southampton, United Kingdom
| | - Li-Min Liu
- School of Physics, Beihang University, Beijing 100191, China
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46
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Puppin M, Polishchuk S, Colonna N, Crepaldi A, Dirin DN, Nazarenko O, De Gennaro R, Gatti G, Roth S, Barillot T, Poletto L, Xian RP, Rettig L, Wolf M, Ernstorfer R, Kovalenko MV, Marzari N, Grioni M, Chergui M. Evidence of Large Polarons in Photoemission Band Mapping of the Perovskite Semiconductor CsPbBr_{3}. PHYSICAL REVIEW LETTERS 2020; 124:206402. [PMID: 32501104 DOI: 10.1103/physrevlett.124.206402] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 03/30/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Lead-halide perovskite (LHP) semiconductors are emergent optoelectronic materials with outstanding transport properties which are not yet fully understood. We find signatures of large polaron formation in the electronic structure of the inorganic LHP CsPbBr_{3} by means of angle-resolved photoelectron spectroscopy. The experimental valence band dispersion shows a hole effective mass of 0.26±0.02 m_{e}, 50% heavier than the bare mass m_{0}=0.17 m_{e} predicted by density functional theory. Calculations of the electron-phonon coupling indicate that phonon dressing of the carriers mainly occurs via distortions of the Pb-Br bond with a Fröhlich coupling parameter α=1.81. A good agreement with our experimental data is obtained within the Feynman polaron model, validating a viable theoretical method to predict the carrier effective mass of LHPs ab initio.
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Affiliation(s)
- M Puppin
- Laboratoire de Spectroscopie Ultrarapide and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC, Station 6, CH-1015 Lausanne, Switzerland
| | - S Polishchuk
- Laboratoire de Spectroscopie Ultrarapide and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC, Station 6, CH-1015 Lausanne, Switzerland
| | - N Colonna
- Theory and Simulations of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - A Crepaldi
- Institute of Physics and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - D N Dirin
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics, EMPA Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - O Nazarenko
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics, EMPA Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - R De Gennaro
- Theory and Simulations of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - G Gatti
- Institute of Physics and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - S Roth
- Institute of Physics and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - T Barillot
- Laboratoire de Spectroscopie Ultrarapide and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC, Station 6, CH-1015 Lausanne, Switzerland
| | - L Poletto
- National Research Council of Italy-Institute of Photonics and Nanotechnologies (CNR-IFN), via Trasea 7, 35131 Padova, Italy
| | - R P Xian
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - M Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - R Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - M V Kovalenko
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics, EMPA Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - N Marzari
- Theory and Simulations of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Grioni
- Institute of Physics and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Chergui
- Laboratoire de Spectroscopie Ultrarapide and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC, Station 6, CH-1015 Lausanne, Switzerland
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47
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Guo C, Meng X, Fu H, Wang Q, Wang H, Tian Y, Peng J, Ma R, Weng Y, Meng S, Wang E, Jiang Y. Probing Nonequilibrium Dynamics of Photoexcited Polarons on a Metal-Oxide Surface with Atomic Precision. PHYSICAL REVIEW LETTERS 2020; 124:206801. [PMID: 32501065 DOI: 10.1103/physrevlett.124.206801] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 01/26/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Understanding the nonequilibrium dynamics of photoexcited polarons at the atomic scale is of great importance for improving the performance of photocatalytic and solar-energy materials. Using a pulsed-laser-combined scanning tunneling microscopy and spectroscopy, here we succeeded in resolving the relaxation dynamics of single polarons bound to oxygen vacancies on the surface of a prototypical photocatalyst, rutile TiO_{2}(110). The visible-light excitation of the defect-derived polarons depletes the polaron states and leads to delocalized free electrons in the conduction band, which is further corroborated by ab initio calculations. We found that the trapping time of polarons becomes considerably shorter when the polaron is bound to two surface oxygen vacancies than that to one. In contrast, the lifetime of photogenerated free electrons is insensitive to the atomic-scale distribution of the defects but correlated with the averaged defect density within a nanometer-sized area. Those results shed new light on the photocatalytically active sites at the metal-oxide surface.
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Affiliation(s)
- Chaoyu Guo
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Physical Science Laboratory, Huairou National Comprehensive Science Centre, Beijing 101400, People's Republic of China
| | - Xiangzhi Meng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Huixia Fu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Qin Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Huimin Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Ye Tian
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Jinbo Peng
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Runze Ma
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yuxiang Weng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Sheng Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
| | - Enge Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Ying Jiang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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48
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Jovic V, Moser S, Papadogianni A, Koch RJ, Rossi A, Jozwiak C, Bostwick A, Rotenberg E, Kennedy JV, Bierwagen O, Smith KE. The Itinerant 2D Electron Gas of the Indium Oxide (111) Surface: Implications for Carbon- and Energy-Conversion Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1903321. [PMID: 31489781 DOI: 10.1002/smll.201903321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Transparent conducting oxides (TCO) have integral and emerging roles in photovoltaic, thermoelectric energy conversion, and more recently, photocatalytic systems. The functional properties of TCOs, and thus their role in these applications, are often mediated by the bulk electronic band structure but are also strongly influenced by the electronic structure of the native surface 2D electron gas (2DEG), particularly under operating conditions. This study investigates the 2DEG, and its response to changes in chemistry, at the (111) surface of the model TCO In2 O3 , through angle resolved and core level X-ray photoemission spectroscopy. It is found that the itinerant charge carriers of the 2DEG reside in two quantum well subbands penetrating up to 65 Å below the surface. The charge carrier concentration of this 2DEG, and thus the high surface n-type conductivity, emerges from donor-type oxygen vacancies of surface character and proves to be remarkably robust against surface absorbents and contamination. The optical transparency, however, may rely on the presence of ubiquitous surface adsorbed oxygen groups and hydrogen defect states that passivate localized oxygen vacancy states in the bandgap of In2 O3 .
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Affiliation(s)
- Vedran Jovic
- National Isotope Center, GNS Science, MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt, Wellington, 5010, New Zealand
- School of Chemical Sciences, The University of Auckland, Auckland, 1010, New Zealand
| | - Simon Moser
- Physikalisches Institut, Universität Würzburg, Würzburg, D-97074, Germany
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alexandra Papadogianni
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, Berlin, 10117, Germany
| | - Roland J Koch
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Antonio Rossi
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Davis, CA, 95616, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John V Kennedy
- National Isotope Center, GNS Science, MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt, Wellington, 5010, New Zealand
| | - Oliver Bierwagen
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, Berlin, 10117, Germany
| | - Kevin E Smith
- Department of Physics, Boston University, Boston, MA, 02215, USA
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49
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Kang M, Ye L, Fang S, You JS, Levitan A, Han M, Facio JI, Jozwiak C, Bostwick A, Rotenberg E, Chan MK, McDonald RD, Graf D, Kaznatcheev K, Vescovo E, Bell DC, Kaxiras E, van den Brink J, Richter M, Prasad Ghimire M, Checkelsky JG, Comin R. Dirac fermions and flat bands in the ideal kagome metal FeSn. NATURE MATERIALS 2020; 19:163-169. [PMID: 31819211 DOI: 10.1038/s41563-019-0531-0] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
A kagome lattice of 3d transition metal ions is a versatile platform for correlated topological phases hosting symmetry-protected electronic excitations and magnetic ground states. However, the paradigmatic states of the idealized two-dimensional kagome lattice-Dirac fermions and flat bands-have not been simultaneously observed. Here, we use angle-resolved photoemission spectroscopy and de Haas-van Alphen quantum oscillations to reveal coexisting surface and bulk Dirac fermions as well as flat bands in the antiferromagnetic kagome metal FeSn, which has spatially decoupled kagome planes. Our band structure calculations and matrix element simulations demonstrate that the bulk Dirac bands arise from in-plane localized Fe-3d orbitals, and evidence that the coexisting Dirac surface state realizes a rare example of fully spin-polarized two-dimensional Dirac fermions due to spin-layer locking in FeSn. The prospect to harness these prototypical excitations in a kagome lattice is a frontier of great promise at the confluence of topology, magnetism and strongly correlated physics.
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Affiliation(s)
- Mingu Kang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Linda Ye
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shiang Fang
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Jhih-Shih You
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Abe Levitan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Minyong Han
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jorge I Facio
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Chris Jozwiak
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Aaron Bostwick
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Eli Rotenberg
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mun K Chan
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Ross D McDonald
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - David Graf
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | | | - Elio Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - David C Bell
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Nanoscale systems, Harvard University, Cambridge, MA, USA
| | - Efthimios Kaxiras
- Department of Physics, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Jeroen van den Brink
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Manuel Richter
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
- Dresden Center for Computational Materials Science (DCMS), TU Dresden, Dresden, Germany
| | - Madhav Prasad Ghimire
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
- Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Joseph G Checkelsky
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
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50
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Nasretdinova V, Gerasimenko YA, Mravlje J, Gatti G, Sutar P, Svetin D, Meden A, Kabanov V, Kuntsevich AY, Grioni M, Mihailovic D. Unveiling the electronic transformations in the semi-metallic correlated-electron transitional oxide Mo 8O 23. Sci Rep 2019; 9:15959. [PMID: 31685868 PMCID: PMC6828745 DOI: 10.1038/s41598-019-52231-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 10/10/2019] [Indexed: 11/17/2022] Open
Abstract
Mo8O23 is a low-dimensional chemically robust transition metal oxide coming from a prospective family of functional materials, MoO3−x, ranging from a wide gap insulator (x = 0) to a metal (x = 1). The large number of stoichometric compounds with intermediate x have widely different properties. In Mo8O23, an unusual charge density wave transition has been suggested to occur above room temperature, but its low temperature behaviour is particularly enigmatic. We present a comprehensive experimental study of the electronic structure associated with various ordering phenomena in this compound, complemented by theory. Density-functional theory (DFT) calculations reveal a cross-over from a semi-metal with vanishing band overlap to narrow-gap semiconductor behaviour with decreasing temperature. A buried Dirac crossing at the zone boundary is confirmed by angle-resolved photoemission spectroscopy (ARPES). Tunnelling spectroscopy (STS) reveals a gradual gap opening corresponding to a metal-to-insulator transition at 343 K in resistivity, consistent with CDW formation and DFT results, but with large non-thermal smearing of the spectra implying strong carrier scattering. At low temperatures, the CDW picture is negated by the observation of a metallic Hall contribution, a non-trivial gap structure in STS below ∼170 K and ARPES spectra, that together represent evidence for the onset of the correlated state at 70 K and the rapid increase of gap size below ∼30 K. The intricate interplay between electronic correlations and the presence of multiple narrow bands near the Fermi level set the stage for metastability and suggest suitability for memristor applications.
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Affiliation(s)
- V Nasretdinova
- Center of Excellence on Nanoscience and Nanotechnology Nanocenter (CENN Nanocenter), Jamova 39, 1000, Ljubljana, Slovenia.
| | - Ya A Gerasimenko
- Center of Excellence on Nanoscience and Nanotechnology Nanocenter (CENN Nanocenter), Jamova 39, 1000, Ljubljana, Slovenia.,Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - J Mravlje
- Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - G Gatti
- Institute of Physics, EPFL, Lausanne, Switzerland
| | - P Sutar
- Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - D Svetin
- Center of Excellence on Nanoscience and Nanotechnology Nanocenter (CENN Nanocenter), Jamova 39, 1000, Ljubljana, Slovenia.,Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - A Meden
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna Pot 113, 1000, Ljubljana, Slovenia
| | - V Kabanov
- Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
| | - A Yu Kuntsevich
- P. N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991, Moscow, Russia.,National Research University Higher School of Economics, Moscow, 101000, Russia
| | - M Grioni
- Institute of Physics, EPFL, Lausanne, Switzerland
| | - D Mihailovic
- Center of Excellence on Nanoscience and Nanotechnology Nanocenter (CENN Nanocenter), Jamova 39, 1000, Ljubljana, Slovenia.,Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.,Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000, Ljubljana, Slovenia
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