1
|
Kafle GP, Liu ZF. Erratum: "Quasiparticle electronic structure of phthalocyanine:TMD interfaces from first-principles GW" [J. Chem. Phys. 155, 214702 (2021)]. J Chem Phys 2024; 161:089901. [PMID: 39172039 DOI: 10.1063/5.0230977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2024] [Accepted: 08/01/2024] [Indexed: 08/23/2024] Open
Affiliation(s)
- Gyanu P Kafle
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
| | - Zhen-Fei Liu
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
| |
Collapse
|
2
|
Qian C, Villafañe V, Soubelet P, Ji P, Stier AV, Finley JJ. Probing Dark Excitons in Monolayer MoS_{2} by Nonlinear Two-Photon Spectroscopy. PHYSICAL REVIEW LETTERS 2024; 133:086902. [PMID: 39241713 DOI: 10.1103/physrevlett.133.086902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 03/28/2024] [Accepted: 07/25/2024] [Indexed: 09/09/2024]
Abstract
We report a new dark exciton in monolayer MoS_{2} using second harmonic generation spectroscopy. Hereby, the spectrally dependent second harmonic generation intensity splits into two branches, and an anticrossing is observed at ∼25 meV blue detuned from the bright neutral exciton. These observations are indicative of coherent quantum interference arising from strong two-photon light-matter interaction with an excitonic state that is dark for single photon interaction. The existence of the dark state is supported by engineering its relaxation to bright localized excitons, mediated by vibrational modes of a proximal nanobeam cavity. We show that two-photon light-matter interaction involving dark states has the potential to control relaxation pathways induced by nanostructuring the local environment. Moreover, our results indicate that dark excitons have significant potential for nonlinear quantum devices based on their nontrivial excitonic photophysics.
Collapse
Affiliation(s)
- Chenjiang Qian
- Walter Schottky Institut and TUM School of Natural Sciences, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | | | | | | | | | | |
Collapse
|
3
|
Ding YM, Yan L, Wu Y, Zhou L. Exciton-Driven and Layer-Independent Linear and Nonlinear Optical Properties in NbOCl 2. J Phys Chem Lett 2024; 15:7191-7198. [PMID: 38968446 DOI: 10.1021/acs.jpclett.4c01677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2024]
Abstract
We investigate the electronic structure and linear and nonlinear [second-harmonic generation (SHG)] spectra of the NbOCl2 monolayer, bilayer, and bulk by using a real-time first-principles approach based on many-body theory. First, the interlayer couplings between NbOCl2 layers are very weak, due to the relatively large interlayer distance, saturation of the p orbital of Cl atoms, and high degree of localization of charge density around the Nb atom for both the lowest conduction band and the highest valence band. Second, the quasiparticle gaps and exciton binding energy for the three systems show layer-dependent features and decrease with an increase in layer thickness. Most importantly, the linear and SHG spectra of the NbOCl2 monolayer, bilayer, and bulk are dominated by strong excitonic resonances and exhibit layer-independent features due to the weak interlayer couplings. Our findings demonstrate that excitonic effects should be included in studying the optical properties of not only two-dimensional materials but also layered bulk materials with weak interlayer couplings.
Collapse
Affiliation(s)
- Yi-Min Ding
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, China
| | - Luo Yan
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, China
- School of Physics, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yu Wu
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, China
| | - Liujiang Zhou
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, China
- School of Physics, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| |
Collapse
|
4
|
Kim SJ, Lebègue S, Ringe S, Kim H. Elucidating Solvatochromic Shifts in Two-Dimensional Photocatalysts by Solving the Bethe-Salpeter Equation Coupled with Implicit Solvation Method. J Phys Chem Lett 2024; 15:4575-4580. [PMID: 38639559 DOI: 10.1021/acs.jpclett.4c00752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Many studies have focused on tailoring the photophysical properties of two-dimensional (2D) materials for photocatalytic (PC) or photoelectrochemical (PEC) applications. To understand the optical properties of 2D materials in solution, we established a computational method that combined the Bethe-Salpeter equation (BSE) calculations with our GW-GPE method, allowing for GW/BSE-level calculations with implicit solvation described using the generalized Poisson equation (GPE). We applied this method to MoS2, phosphorene (PP), and g-C3N4 and found that when the solvent dielectric increased, it reduced the exciton binding energy and quasiparticle bandgap, resulting in almost no solvatochromic shift in the excitonic peaks of MoS2 and PP, which is consistent with previous experiments. However, our calculations predicted that the solvent dielectric had a significant impact on the excitonic properties of g-C3N4, exhibiting a large solvatochromic shift. We expect that our GW/BSE-GPE method will offer insights into the design of 2D materials for PC and PEC applications.
Collapse
Affiliation(s)
- Se-Jun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sébastien Lebègue
- Université de Lorraine and CNRS, LPCT, UMR 7019, Vandoeuvre-lès-Nancy 54506, France
| | - Stefan Ringe
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Hyungjun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
| |
Collapse
|
5
|
Carey B, Wessling NK, Steeger P, Schmidt R, Michaelis de Vasconcellos S, Bratschitsch R, Arora A. Giant Faraday rotation in atomically thin semiconductors. Nat Commun 2024; 15:3082. [PMID: 38600090 PMCID: PMC11006678 DOI: 10.1038/s41467-024-47294-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 03/21/2024] [Indexed: 04/12/2024] Open
Abstract
Faraday rotation is a fundamental effect in the magneto-optical response of solids, liquids and gases. Materials with a large Verdet constant find applications in optical modulators, sensors and non-reciprocal devices, such as optical isolators. Here, we demonstrate that the plane of polarization of light exhibits a giant Faraday rotation of several degrees around the A exciton transition in hBN-encapsulated monolayers of WSe2 and MoSe2 under moderate magnetic fields. This results in the highest known Verdet constant of -1.9 × 107 deg T-1 cm-1 for any material in the visible regime. Additionally, interlayer excitons in hBN-encapsulated bilayer MoS2 exhibit a large Verdet constant (VIL ≈ +2 × 105 deg T-1 cm-2) of opposite sign compared to A excitons in monolayers. The giant Faraday rotation is due to the giant oscillator strength and high g-factor of the excitons in atomically thin semiconducting transition metal dichalcogenides. We deduce the complete in-plane complex dielectric tensor of hBN-encapsulated WSe2 and MoSe2 monolayers, which is vital for the prediction of Kerr, Faraday and magneto-circular dichroism spectra of 2D heterostructures. Our results pose a crucial advance in the potential usage of two-dimensional materials in ultrathin optical polarization devices.
Collapse
Affiliation(s)
- Benjamin Carey
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
- School of Mathematics and Physics, The University of Queensland, St Lucia, QLD, Australia
| | - Nils Kolja Wessling
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
- Institute of Photonics, Department of Physics, University of Strathclyde, 99 George Street, Glasgow, UK
| | - Paul Steeger
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
| | - Robert Schmidt
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
| | | | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany.
| | - Ashish Arora
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany.
- Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, Maharashtra, India.
| |
Collapse
|
6
|
Bayramov AH, Bagiyev EA, Alizade EH, Jalilli JN, Mamedov NT, Jahangirli ZA, Asadullayeva SG, Aliyeva YN, Cuscunà M, Lorenzo D, Esposito M, Balestra G, Simeone D, Tobaldi DM, Abou-Ras D, Schorr S. Two-Channel Indirect-Gap Photoluminescence and Competition between the Conduction Band Valleys in Few-Layer MoS 2. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 14:96. [PMID: 38202552 PMCID: PMC10780461 DOI: 10.3390/nano14010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024]
Abstract
MoS2 is a two-dimensional layered transition metal dichalcogenide with unique electronic and optical properties. The fabrication of ultrathin MoS2 is vitally important, since interlayer interactions in its ultrathin varieties will become thickness-dependent, providing thickness-governed tunability and diverse applications of those properties. Unlike with a number of studies that have reported detailed information on direct bandgap emission from MoS2 monolayers, reliable experimental evidence for thickness-induced evolution or transformation of the indirect bandgap remains scarce. Here, the sulfurization of MoO3 thin films with nominal thicknesses of 30 nm, 5 nm and 3 nm was performed. All sulfurized samples were examined at room temperature with spectroscopic ellipsometry and photoluminescence spectroscopy to obtain information about their dielectric function and edge emission spectra. This investigation unveiled an indirect-to-indirect crossover between the transitions, associated with two different Λ and K valleys of the MoS2 conduction band, by thinning its thickness down to a few layers.
Collapse
Affiliation(s)
- Ayaz H. Bayramov
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
| | - Elnur A. Bagiyev
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
| | - Elvin H. Alizade
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
| | - Javid N. Jalilli
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
| | - Nazim T. Mamedov
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
- Institute of Physical Problems, Baku State University, Ministry of Science and Education, Baku Az1148, Azerbaijan;
| | - Zakir A. Jahangirli
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
- Institute of Physical Problems, Baku State University, Ministry of Science and Education, Baku Az1148, Azerbaijan;
| | - Saida G. Asadullayeva
- Institute of Physics, Ministry of Science and Education, Baku Az1143, Azerbaijan; (A.H.B.); (E.H.A.); (S.G.A.)
| | - Yegana N. Aliyeva
- Institute of Physical Problems, Baku State University, Ministry of Science and Education, Baku Az1148, Azerbaijan;
| | - Massimo Cuscunà
- National Research Council, Institute of Nanotechnology (NANOTEC), University c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy; (D.L.); (M.E.); (G.B.); (D.S.); (D.M.T.)
| | - Daniela Lorenzo
- National Research Council, Institute of Nanotechnology (NANOTEC), University c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy; (D.L.); (M.E.); (G.B.); (D.S.); (D.M.T.)
| | - Marco Esposito
- National Research Council, Institute of Nanotechnology (NANOTEC), University c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy; (D.L.); (M.E.); (G.B.); (D.S.); (D.M.T.)
| | - Gianluca Balestra
- National Research Council, Institute of Nanotechnology (NANOTEC), University c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy; (D.L.); (M.E.); (G.B.); (D.S.); (D.M.T.)
- Department of Mathematics and Physics ‘‘Ennio De Giorgi”, University of Salento, c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy
| | - Daniela Simeone
- National Research Council, Institute of Nanotechnology (NANOTEC), University c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy; (D.L.); (M.E.); (G.B.); (D.S.); (D.M.T.)
| | - David Maria Tobaldi
- National Research Council, Institute of Nanotechnology (NANOTEC), University c/o Campus Ecotekne, Via per Monteroni, 73100 Lecce, Italy; (D.L.); (M.E.); (G.B.); (D.S.); (D.M.T.)
| | - Daniel Abou-Ras
- Helmholtz-Zentrum Berlin for Materials and Energy (HZB), Department of Structure and Dynamics of Energy Materials, 14109 Berlin, Germany; (D.A.-R.); (S.S.)
| | - Susan Schorr
- Helmholtz-Zentrum Berlin for Materials and Energy (HZB), Department of Structure and Dynamics of Energy Materials, 14109 Berlin, Germany; (D.A.-R.); (S.S.)
- Institute of Geological Sciences, Free University of Berlin, 14195 Berlin, Germany
| |
Collapse
|
7
|
Tugchin BN, Doolaard N, Barreda AI, Zhang Z, Romashkina A, Fasold S, Staude I, Eilenberger F, Pertsch T. Photoluminescence Enhancement of Monolayer WS 2 by n-Doping with an Optically Excited Gold Disk. NANO LETTERS 2023; 23:10848-10855. [PMID: 37967849 PMCID: PMC10723068 DOI: 10.1021/acs.nanolett.3c03053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/08/2023] [Indexed: 11/17/2023]
Abstract
In nanophotonics and quantum optics, we aim to control and manipulate light with tailored nanoscale structures. Hybrid systems of nanostructures and atomically thin materials are of interest here, as they offer rich physics and versatility due to the interaction between photons, plasmons, phonons, and excitons. In this study, we explore the optical and electronic properties of a hybrid system, a naturally n-doped monolayer WS2 covering a gold disk. We demonstrate that the nonresonant excitation of the gold disk in the high absorption regime efficiently generates hot carriers via localized surface plasmon excitation, which n-dope the monolayer WS2 and enhance the photoluminescence emission by regulating the multiexciton population and stabilizing the neutral exciton emission. The results are relevant to the further development of nanotransistors in photonic circuits and optoelectronic applications.
Collapse
Affiliation(s)
- Bayarjargal N. Tugchin
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
| | - Nathan Doolaard
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
| | - Angela I. Barreda
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
- Institute
of Solid State Physics, Friedrich Schiller
University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
- Group
of Displays and Photonics Applications, Carlos III University of Madrid, Avda. de la Universidad, 30, Leganés, 28911 Madrid, Spain
| | - Zifei Zhang
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
| | - Anastasia Romashkina
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
| | - Stefan Fasold
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
- Vistec
Electron Beam GmbH, 07743 Jena, Germany
| | - Isabelle Staude
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
- Institute
of Solid State Physics, Friedrich Schiller
University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Falk Eilenberger
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
- Fraunhofer-Institute
for Applied Optics and Precision Engineering IOF, Albert-Einstein-Straße 7, 07745 Jena, Germany
| | - Thomas Pertsch
- Institute
of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 6, 07745 Jena, Germany
- Fraunhofer-Institute
for Applied Optics and Precision Engineering IOF, Albert-Einstein-Straße 7, 07745 Jena, Germany
| |
Collapse
|
8
|
Sun X, Lu Z, Lu Y. Enhanced interactions of excitonic complexes in free-standing WS 2. NANOSCALE 2023. [PMID: 37937449 DOI: 10.1039/d3nr04594c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Excitonic complexes, bound states of electrons and holes, provide a promising platform in monolayer transition-metal dichalcogenide (TMDC) semiconductors for investigating diverse many-body interaction phenomena. The surrounding dielectric environment has been found to strongly influence the excitonic properties of the TMDC monolayers. While the impact of different dielectric surroundings on two-dimensional semiconductor materials and their strong correlations have been well studied, the effects on exciton formation and its properties resulting from a further reduction in dielectric screening remain elusive. In this study, we examined free-standing tungsten disulfide (WS2) monolayers, where the efficient generation of higher-order correlated excitonic complexes is readily observed. This phenomenon arises from the effective mutual interactions among excitons and internal carriers, attributed to the modulated exciton dynamics generated by the further reduced dielectric screening effect in the freestanding structure. The formation efficiency of excitonic complexes is enhanced and the multiple biexciton species (five particles such as charged biexcitons and acceptor/donor-bound biexcitons) are successfully induced under low excitation intensity and moderate temperature conditions. Our findings offer valuable insights into the influence of the dielectric environment on exciton interactions and enable a productive avenue for exploring fundamental many-body interactions, providing new possibilities for dielectric engineering of atomic thin semiconductors.
Collapse
Affiliation(s)
- Xueqian Sun
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia
| | - Zhuoyuan Lu
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia
- Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, the Australian National University, Canberra, ACT, 2601, Australia.
| |
Collapse
|
9
|
Jadczak J, Debus J, Olejnik J, Ho CH, Watanabe K, Taniguchi T, Bryja L. Biexciton and Singlet Trion Upconvert Exciton Photoluminescence in a MoSe 2 Monolayer Supported by Acoustic and Optical K-Valley Phonons. J Phys Chem Lett 2023; 14:8702-8708. [PMID: 37733953 PMCID: PMC10561254 DOI: 10.1021/acs.jpclett.3c01982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Transition metal dichalcogenide monolayers represent unique platforms for studying both electronic and phononic interactions as well as intra- and intervalley exciton complexes. Here, we investigate the upconversion of exciton photoluminescence in MoSe2 monolayers. Within the nominal transparency window of MoSe2 the exciton emission is enhanced for resonantly addressing the spin-singlet negative trion and neutral biexciton at a few tens of meV below the neutral exciton transition. We identify that the A'1 optical phonon at the K valley provides the energy gain in the upconversion process at the trion resonance, while ZA(K) phonons with their spin- and valley-switching properties support the biexciton driven upconversion of the exciton emission. Interestingly, the latter upconversion process yields unpolarized exciton photoluminescence, while the former also leads to circularly polarized emission. Our study highlights high-order exciton complexes interacting with optical and acoustic K-valley phonons and upconverting light into the bright exciton.
Collapse
Affiliation(s)
- Joanna Jadczak
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Joerg Debus
- Department
of Physics, TU Dortmund University, 44227 Dortmund, Germany
| | - Justyna Olejnik
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Ching-Hwa Ho
- Graduate
Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Kenji Watanabe
- National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Leszek Bryja
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| |
Collapse
|
10
|
Reboredo FA, Kent PRC, Krogel JT. Evaluation of the excitation spectra with diffusion Monte Carlo on an auxiliary bosonic ground state. J Chem Phys 2023; 159:114118. [PMID: 37724730 DOI: 10.1063/5.0155513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 08/29/2023] [Indexed: 09/21/2023] Open
Abstract
We aim to improve upon the variational Monte Carlo (VMC) approach for excitations replacing the Jastrow factor by an auxiliary bosonic (AB) ground state and multiplying it by a fermionic component factor. The instantaneous change in imaginary time of an arbitrary excitation in the original interacting fermionic system is obtained by measuring observables via the ground-state distribution of walkers of an AB system that is subject to an auxiliary effective potential. The effective potential is used to (i) drive the AB system's ground-state configuration space toward the configuration space of the excitations of the original fermionic system and (ii) subtract from a diffusion Monte Carlo (DMC) calculation contributions that can be included in conventional approximations, such as mean-field and configuration interaction (CI) methods. In this novel approach, the AB ground state is treated statistically in DMC, whereas the fermionic component of the original system is expanded in a basis. The excitation energies of the fermionic eigenstates are obtained by sampling a fermion-boson coupling term on the AB ground state. We show that this approach can take advantage of and correct for approximate eigenstates obtained via mean-field calculations or truncated interactions. We demonstrate that the AB ground-state factor incorporates the correlations missed by standard Jastrow factors, further reducing basis truncation errors. Relevant parts of the theory have been tested in soluble model systems and exhibit excellent agreement with exact analytical data and CI and VMC approaches. In particular, for limited basis set expansions and sufficient statistics, AB approaches outperform CI and VMC in terms of basis size for the same systems. The implementation of this method in current codes, despite being demanding, will be facilitated by reusing procedures already developed for calculating ground-state properties with DMC and excitations with VMC.
Collapse
Affiliation(s)
- Fernando A Reboredo
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Paul R C Kent
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jaron T Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
11
|
Xu N, Hong D, Liang B, Qiu L, Tian Y, Li S. Lattice Vacancy Induced Energy Renormalization of Photonic Quasiparticles in Two-Dimensional Semiconductors. ACS NANO 2023; 17:16904-16911. [PMID: 37603694 DOI: 10.1021/acsnano.3c03996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Coulomb interactions among dense charges and quasiparticle energy renormalization are at the center of quantum science because they significantly reshape the fundamental electronic and photonic properties of materials. While lattice vacancies are ubiquitous in solid materials, their physical effect on the Coulomb interaction among quasiparticles is normally weak and negligible. Here we show that in atomically thin semiconductors the presence of lattice vacancies emerges as an important but unexplored origin for the nontrivial renormalization of quasiparticle binding energies, due to the subtle modification of overall dielectric functions at low dimensionality. Such a renormalization effect leads to unusual reduction in the energy scales of photonic quasiparticles and red shifts of photoluminescence as the density of lattice vacancies increases. With strict configurative form factors derived, a dielectric screening model is also established for the generalized trilayer systems to capture the fine modification in the energy scales of quasiparticles and to elucidate the dielectric functions versus realistic Bohr lengths. This finding highlights the essential but commonly neglected role of lattice vacancies and deciphers the longstanding enigma of unpredictable photoluminescent line shifts in low-dimensional systems.
Collapse
Affiliation(s)
- Ning Xu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Daocheng Hong
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Binxi Liang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Lipeng Qiu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Yuxi Tian
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Songlin Li
- School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210023, People's Republic of China
| |
Collapse
|
12
|
van Loon EGCP, Schüler M, Springer D, Sangiovanni G, Tomczak JM, Wehling TO. Coulomb engineering of two-dimensional Mott materials. NPJ 2D MATERIALS AND APPLICATIONS 2023; 7:47. [PMID: 38665482 PMCID: PMC11041779 DOI: 10.1038/s41699-023-00408-x] [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: 10/14/2022] [Accepted: 06/15/2023] [Indexed: 04/28/2024]
Abstract
Two-dimensional materials can be strongly influenced by their surroundings. A dielectric environment screens and reduces the Coulomb interaction between electrons in the two-dimensional material. Since in Mott materials the Coulomb interaction is responsible for the insulating state, manipulating the dielectric screening provides direct control over Mottness. Our many-body calculations reveal the spectroscopic fingerprints of such Coulomb engineering: we demonstrate eV-scale changes to the position of the Hubbard bands and show a Coulomb engineered insulator-to-metal transition. Based on our proof-of-principle calculations, we discuss the (feasible) conditions under which our scenario of Coulomb engineering of Mott materials can be realized experimentally.
Collapse
Affiliation(s)
- Erik G. C. P. van Loon
- Mathematical Physics Division, Department of Physics, Lund University, Lund, Sweden
- Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- Bremen Center for Computational Materials Science, Universität Bremen, Am Fallturm 1a, 28359 Bremen, Germany
| | - Malte Schüler
- Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- Bremen Center for Computational Materials Science, Universität Bremen, Am Fallturm 1a, 28359 Bremen, Germany
| | - Daniel Springer
- Institute of Solid State Physics, TU Wien, A-1040 Vienna, Austria
- Institute of Advanced Research in Artificial Intelligence, IARAI, A-1030 Vienna, Austria
| | - Giorgio Sangiovanni
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Jan M. Tomczak
- Institute of Solid State Physics, TU Wien, A-1040 Vienna, Austria
- Department of Physics, King’s College London, Strand, London, WC2R 2LS UK
| | - Tim O. Wehling
- I. Institute of Theoretical Physics, University of Hamburg, D-22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, D-22761 Hamburg, Germany
| |
Collapse
|
13
|
Louca C, Genco A, Chiavazzo S, Lyons TP, Randerson S, Trovatello C, Claronino P, Jayaprakash R, Hu X, Howarth J, Watanabe K, Taniguchi T, Dal Conte S, Gorbachev R, Lidzey DG, Cerullo G, Kyriienko O, Tartakovskii AI. Interspecies exciton interactions lead to enhanced nonlinearity of dipolar excitons and polaritons in MoS 2 homobilayers. Nat Commun 2023; 14:3818. [PMID: 37369664 DOI: 10.1038/s41467-023-39358-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Nonlinear interactions between excitons strongly coupled to light are key for accessing quantum many-body phenomena in polariton systems. Atomically-thin two-dimensional semiconductors provide an attractive platform for strong light-matter coupling owing to many controllable excitonic degrees of freedom. Among these, the recently emerged exciton hybridization opens access to unexplored excitonic species, with a promise of enhanced interactions. Here, we employ hybridized interlayer excitons (hIX) in bilayer MoS2 to achieve highly nonlinear excitonic and polaritonic effects. Such interlayer excitons possess an out-of-plane electric dipole as well as an unusually large oscillator strength allowing observation of dipolar polaritons (dipolaritons) in bilayers in optical microcavities. Compared to excitons and polaritons in MoS2 monolayers, both hIX and dipolaritons exhibit ≈ 8 times higher nonlinearity, which is further strongly enhanced when hIX and intralayer excitons, sharing the same valence band, are excited simultaneously. This provides access to an unusual nonlinear regime which we describe theoretically as a mixed effect of Pauli exclusion and exciton-exciton interactions enabled through charge tunnelling. The presented insight into many-body interactions provides new tools for accessing few-polariton quantum correlations.
Collapse
Affiliation(s)
- Charalambos Louca
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK.
| | - Armando Genco
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy.
| | - Salvatore Chiavazzo
- Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4PY, UK
| | - Thomas P Lyons
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- RIKEN Center for Emergent Matter Science, Wako, Saitama, 351-0198, Japan
| | - Sam Randerson
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Chiara Trovatello
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
- Department of Mechanical Engineering, Columbia University, NY, 10027, New York, USA
| | - Peter Claronino
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Department of Physics and Mathematics, University of Hull, Rober Blackburn, Hull HU6 7RX, UK
| | - Rahul Jayaprakash
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Xuerong Hu
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - James Howarth
- National Graphene Institute, University of Manchester, Manchester, UK
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Stefano Dal Conte
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
| | - Roman Gorbachev
- National Graphene Institute, University of Manchester, Manchester, UK
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
| | - David G Lidzey
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
| | - Oleksandr Kyriienko
- Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4PY, UK
| | | |
Collapse
|
14
|
Li WH, Lin JD, Lo PY, Peng GH, Hei CY, Chen SY, Cheng SJ. The Key Role of Non-Local Screening in the Environment-Insensitive Exciton Fine Structures of Transition-Metal Dichalcogenide Monolayers. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13111739. [PMID: 37299642 DOI: 10.3390/nano13111739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/21/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023]
Abstract
In this work, we present a comprehensive theoretical and computational investigation of exciton fine structures of WSe2-monolayers, one of the best-known two-dimensional (2D) transition-metal dichalcogenides (TMDs), in various dielectric-layered environments by solving the first-principles-based Bethe-Salpeter equation. While the physical and electronic properties of atomically thin nanomaterials are normally sensitive to the variation of the surrounding environment, our studies reveal that the influence of the dielectric environment on the exciton fine structures of TMD-MLs is surprisingly limited. We point out that the non-locality of Coulomb screening plays a key role in suppressing the dielectric environment factor and drastically shrinking the fine structure splittings between bright exciton (BX) states and various dark-exciton (DX) states of TMD-MLs. The intriguing non-locality of screening in 2D materials can be manifested by the measurable non-linear correlation between the BX-DX splittings and exciton-binding energies by varying the surrounding dielectric environments. The revealed environment-insensitive exciton fine structures of TMD-ML suggest the robustness of prospective dark-exciton-based optoelectronics against the inevitable variation of the inhomogeneous dielectric environment.
Collapse
Affiliation(s)
- Wei-Hua Li
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Jhen-Dong Lin
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Ping-Yuan Lo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Guan-Hao Peng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Ching-Yu Hei
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Shao-Yu Chen
- Center of Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan
- Center of Atomic Initiative for New Material, National Taiwan University, Taipei 106, Taiwan
| | - Shun-Jen Cheng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| |
Collapse
|
15
|
Niebur A, Söll A, Haizmann P, Strolka O, Rudolph D, Tran K, Renz F, Frauendorf AP, Hübner J, Peisert H, Scheele M, Lauth J. Untangling the intertwined: metallic to semiconducting phase transition of colloidal MoS 2 nanoplatelets and nanosheets. NANOSCALE 2023; 15:5679-5688. [PMID: 36861175 DOI: 10.1039/d3nr00096f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
2D semiconducting transition metal dichalcogenides (TMDCs) are highly promising materials for future spin- and valleytronic applications and exhibit an ultrafast response to external (optical) stimuli which is essential for optoelectronics. Colloidal nanochemistry on the other hand is an emerging alternative for the synthesis of 2D TMDC nanosheet (NS) ensembles, allowing for the control of the reaction via tunable precursor and ligand chemistry. Up to now, wet-chemical colloidal syntheses yielded intertwined/agglomerated NSs with a large lateral size. Here, we show a synthesis method for 2D mono- and bilayer MoS2 nanoplatelets with a particularly small lateral size (NPLs, 7.4 nm ± 2.2 nm) and MoS2 NSs (22 nm ± 9 nm) as a reference by adjusting the molybdenum precursor concentration in the reaction. We find that in colloidal 2D MoS2 syntheses initially a mixture of the stable semiconducting and the metastable metallic crystal phase is formed. 2D MoS2 NPLs and NSs then both undergo a full transformation to the semiconducting crystal phase by the end of the reaction, which we quantify by X-ray photoelectron spectroscopy. Phase pure semiconducting MoS2 NPLs with a lateral size approaching the MoS2 exciton Bohr radius exhibit strong additional lateral confinement, leading to a drastically shortened decay of the A and B exciton which is characterized by ultrafast transient absorption spectroscopy. Our findings represent an important step for utilizing colloidal TMDCs, for example small MoS2 NPLs represent an excellent starting point for the growth of heterostructures for future colloidal photonics.
Collapse
Affiliation(s)
- André Niebur
- Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, D-30167 Hannover, Germany.
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Hannover, Germany
| | - Aljoscha Söll
- Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, D-30167 Hannover, Germany.
| | - Philipp Haizmann
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Onno Strolka
- Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, D-30167 Hannover, Germany.
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Hannover, Germany
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Dominik Rudolph
- Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, D-30167 Hannover, Germany.
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Hannover, Germany
| | - Kevin Tran
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, D-30167 Hannover, Germany
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167 Hannover, Germany
| | - Franz Renz
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, D-30167 Hannover, Germany
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167 Hannover, Germany
| | - André Philipp Frauendorf
- Institute of Solid State Physics, Leibniz University Hannover, Appelstr. 2, D-30167 Hannover, Germany
| | - Jens Hübner
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167 Hannover, Germany
- Institute of Solid State Physics, Leibniz University Hannover, Appelstr. 2, D-30167 Hannover, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Marcus Scheele
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Jannika Lauth
- Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3a, D-30167 Hannover, Germany.
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Hannover, Germany
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167 Hannover, Germany
| |
Collapse
|
16
|
Reidy K, Majchrzak PE, Haas B, Thomsen JD, Konečná A, Park E, Klein J, Jones AJH, Volckaert K, Biswas D, Watson MD, Cacho C, Narang P, Koch CT, Ulstrup S, Ross FM, Idrobo JC. Direct Visualization of Subnanometer Variations in the Excitonic Spectra of 2D/3D Semiconductor/Metal Heterostructures. NANO LETTERS 2023; 23:1068-1076. [PMID: 36637381 DOI: 10.1021/acs.nanolett.2c04749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The integration of metallic contacts with two-dimensional (2D) semiconductors is routinely required for the fabrication of nanoscale devices. However, nanometer-scale variations in the 2D/metal interface can drastically alter the local optoelectronic properties. Here, we map local excitonic changes of the 2D semiconductor MoS2 in contact with Au. We utilize a suspended and epitaxially grown 2D/metal platform that allows correlated electron energy-loss spectroscopy (EELS) and angle resolved photoelectron spectroscopy (nanoARPES) mapping. Spatial localization of MoS2 excitons uncovers an additional EELS peak related to the MoS2/Au interface. NanoARPES measurements indicate that Au-S hybridization decreases substantially with distance from the 2D/metal interface, suggesting that the observed EELS peak arises due to dielectric screening of the excitonic Coulomb interaction. Our results suggest that increasing the van der Waals distance could optimize excitonic spectra of mixed-dimensional 2D/3D interfaces and highlight opportunities for Coulomb engineering of exciton energies by the local dielectric environment or moiré engineering.
Collapse
Affiliation(s)
- Kate Reidy
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | - Benedikt Haas
- Department of Physics & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Joachim Dahl Thomsen
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Andrea Konečná
- Central European Institute of Technology, Brno University of Technology, 61200 Brno, Czech Republic
| | - Eugene Park
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Julian Klein
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alfred J H Jones
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Klara Volckaert
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Deepnarayan Biswas
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Matthew D Watson
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Cephise Cacho
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Prineha Narang
- College of Letters and Science, Physical Sciences, UCLA, Los Angeles, California 90095, United States
| | - Christoph T Koch
- Department of Physics & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Søren Ulstrup
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Juan Carlos Idrobo
- Materials Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
| |
Collapse
|
17
|
Wang K, Paulus B. Cluster Formation Effect of Water on Pristine and Defective MoS 2 Monolayers. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:229. [PMID: 36677982 PMCID: PMC9864297 DOI: 10.3390/nano13020229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/23/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The structure and electronic properties of the molybdenum disulfide (MoS2) monolayer upon water cluster adsorption are studied using density functional theory and the optical properties are further analyzed with the Bethe-Salpeter equation (BSE). Our results reveal that the water clusters are electron acceptors, and the acceptor tendency tends to increase with the size of the water cluster. The electronic band gap of both pristine and defective MoS2 is rather insensitive to water cluster adsorbates, as all the clusters are weakly bound to the MoS2 surface. However, our calculations on the BSE level show that the adsorption of the water cluster can dramatically redshift the optical absorption for both pristine and defective MoS2 monolayers. The binding energy of the excitons of MoS2 is greatly enhanced with the increasing size of the water cluster and finally converges to a value of approximately 1.16 eV and 1.09 eV for the pristine and defective MoS2 monolayers, respectively. This illustrates that the presence of the water cluster could localize the excitons of MoS2, thereby greatly enhance the excitonic binding energy.
Collapse
|
18
|
Zhumagulov YV, Vagov A, Gulevich DR, Perebeinos V. Electrostatic and Environmental Control of the Trion Fine Structure in Transition Metal Dichalcogenide Monolayers. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3728. [PMID: 36364505 PMCID: PMC9656490 DOI: 10.3390/nano12213728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Charged excitons or trions are essential for optical spectra in low-dimensional doped monolayers (ML) of transitional metal dichalcogenides (TMDC). Using a direct diagonalization of the three-body Hamiltonian, we calculate the low-lying trion states in four types of TMDC MLs as a function of doping and dielectric environment. We show that the fine structure of the trion is the result of the interplay between the spin-valley fine structure of the single-particle bands and the exchange interaction. We demonstrate that by variations of the doping and dielectric environment, the fine structure of the trion energy can be tuned, leading to anticrossing of the bright and dark states, with substantial implications for the optical spectra of the TMDC ML.
Collapse
Affiliation(s)
| | - Alexei Vagov
- Faculty of Physics, National Research University Higher School of Economics, 101000 Moscow, Russia
| | | | - Vasili Perebeinos
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| |
Collapse
|
19
|
Nanocavity-induced trion emission from atomically thin WSe 2. Sci Rep 2022; 12:15861. [PMID: 36151265 PMCID: PMC9508186 DOI: 10.1038/s41598-022-20226-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/09/2022] [Indexed: 11/08/2022] Open
Abstract
Exciton is a bosonic quasiparticle consisting of a pair of electron and hole, with promising potentials for optoelectronic device applications, such as exciton transistors, photodetectors and light emitting devices. However, the charge-neutral nature of excitons renders them challenging to manipulate using electronics. Here we present the generation of trions, a form of charged excitons, together with enhanced exciton resonance in monolayer WSe2. The excitation of the trion quasiparticles is achieved by the hot carrier transport from the integrated gold plasmonic nanocavity, formed by embedding monolayer WSe2 between gold nanoparticles and a gold film. The nanocavity-induced negatively charged trions provide a promising route for the manipulation of excitons, essential for the construction of all-exciton information processing circuits.
Collapse
|
20
|
Liao Y, Huang Z, Qiao H, Zhou Y, Yang H, Qi X. Stable and flexible photodetector based on liquid-phase exfoliated titanium disulfide nanosheets. NANOTECHNOLOGY 2022; 33:485707. [PMID: 35896084 DOI: 10.1088/1361-6528/ac8488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Herein, the TiS2nanosheets (NSs) are prepared from the TiS2bulk by the liquid-phase exfoliation to fabricate photoelectrochemical-type (PEC) photodetector. SEM images and Raman spectra show the successful acquisition of the TiS2NSs. The as-prepared TiS2photodetector shows self-powered ability with an applicable photoresponsivity that is about 0.37μA W-1under zero bias potential and 80 mW cm-2visible light, and the response time of rise is 0.67 s and the decay time is 2.81 s. In this case, the photodetector is made of ITO-coated polyethylene terephthalate (PET), so it can maintain stable performance under the bending conditions. These results display that the as-prepared photodetector has excellent photoelectric properties, which facilitates the development of TiS2NSs in optoelectronic devices.
Collapse
Affiliation(s)
- Yanmo Liao
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, People's Republic of China
| | - Zongyu Huang
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, People's Republic of China
- Hunan Key Laboratory of Two-Dimensional Materials, Hunan University, Changsha 410082, People's Republic of China
| | - Hui Qiao
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, People's Republic of China
| | - Yang Zhou
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, People's Republic of China
| | - Han Yang
- School of Physics and Electronic Engineering, Hubei University of Arts and Science, Xiangyang 441053, People's Republic of China
| | - Xiang Qi
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, People's Republic of China
| |
Collapse
|
21
|
Ji J, Choi JH. Recent progress in 2D hybrid heterostructures from transition metal dichalcogenides and organic layers: properties and applications in energy and optoelectronics fields. NANOSCALE 2022; 14:10648-10689. [PMID: 35839069 DOI: 10.1039/d2nr01358d] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Atomically thin transition metal dichalcogenides (TMDs) present extraordinary optoelectronic, electrochemical, and mechanical properties that have not been accessible in bulk semiconducting materials. Recently, a new research field, 2D hybrid heteromaterials, has emerged upon integrating TMDs with molecular systems, including organic molecules, polymers, metal-organic frameworks, and carbonaceous materials, that can tailor the TMD properties and exploit synergetic effects. TMD-based hybrid heterostructures can meet the demands of future optoelectronics, including supporting flexible, transparent, and ultrathin devices, and energy-based applications, offering high energy and power densities with long cycle lives. To realize such applications, it is necessary to understand the interactions between the hybrid components and to develop strategies for exploiting the distinct benefits of each component. Here, we provide an overview of the current understanding of the new phenomena and mechanisms involved in TMD/organic hybrids and potential applications harnessing such valuable materials in an insightful way. We highlight recent discoveries relating to multicomponent hybrid materials. Finally, we conclude this review by discussing challenges related to hybrid heteromaterials and presenting future directions and opportunities in this research field.
Collapse
Affiliation(s)
- Jaehoon Ji
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
| | - Jong Hyun Choi
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
| |
Collapse
|
22
|
Reidy K, Thomsen JD, Lee HY, Zarubin V, Yu Y, Wang B, Pham T, Periwal P, Ross FM. Mechanisms of Quasi van der Waals Epitaxy of Three-Dimensional Metallic Nanoislands on Suspended Two-Dimensional Materials. NANO LETTERS 2022; 22:5849-5858. [PMID: 35852159 DOI: 10.1021/acs.nanolett.2c01682] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Understanding structure at the interface between two-dimensional (2D) materials and 3D metals is crucial for designing novel 2D/3D heterostructures and improving the performance of many 2D material devices. Here, we quantify and discuss the 2D/3D interface structure and the 3D morphology in several materials systems. We first deposit faceted Au nanoislands on graphene and transition metal dichalcogenides, using measurements of the equilibrium island shape to determine values for the 2D/Au interface energy and examining the role of surface reconstructions, chemical identity, and defects on the grown structures. We then deposit the technologically relevant metals Ti and Nb under conditions where kinetic rather than thermodynamic factors govern growth. We describe a transition from dendritic to faceted islands as a function of growth temperature and discuss the factors determining island shape in these materials systems. Finally, we show that suspended 2D materials enable the fabrication of a novel type of 3D/2D/3D heterostructure and discuss the growth mechanism. We suggest that emerging nanodevices will utilize versatile fabrication of 2D/3D heterostructures with well-characterized interfaces and morphologies.
Collapse
Affiliation(s)
- Kate Reidy
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Joachim Dahl Thomsen
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hae Yeon Lee
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Vera Zarubin
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yang Yu
- Raith America Inc., International Applications Center, 300 Jordan Road, Troy, New York 12180, United States
| | - Baoming Wang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Thang Pham
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Priyanka Periwal
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
23
|
Hight-Huf N, Pagaduan JN, Katsumata R, Emrick T, Barnes MD. Stabilization of Three-Particle Excitations in Monolayer MoS 2 by Fluorinated Methacrylate Polymers. J Phys Chem Lett 2022; 13:4794-4799. [PMID: 35613709 DOI: 10.1021/acs.jpclett.2c01150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
While extrinsic factors, such as substrates and chemical doping, are known to strongly influence visible photoemission from monolayer MoS2, key fundamental knowledge for p-type polymeric dopants is lacking. We investigated perturbations to the electronic environment of 2D MoS2 using fluorinated polymer coatings and specifically studied stabilization of three-particle states by monitoring changes in intensities and emission maxima of three-particle and two-particle emissions. We calculated changes in carrier density and trion binding energy, the latter having an additional contribution from MoS2 polarization by the polymer. Polarization is further suggested by Kelvin probe force microscopy (KPFM) measurements of large Fermi level shifts. Changes similar in magnitude, but opposite in sign, were observed in 2D MoS2 coated with an analogous nonfluorinated polymer. These findings highlight the important interplay between electron exchange and electrostatic interactions at the interface between polymers and transition metal dichalcogenides (TMDCs), which govern fundamental electronic properties relevant to next-generation devices.
Collapse
|
24
|
Bieniek M, Sadecka K, Szulakowska L, Hawrylak P. Theory of Excitons in Atomically Thin Semiconductors: Tight-Binding Approach. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1582. [PMID: 35564291 PMCID: PMC9104105 DOI: 10.3390/nano12091582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 02/01/2023]
Abstract
Atomically thin semiconductors from the transition metal dichalcogenide family are materials in which the optical response is dominated by strongly bound excitonic complexes. Here, we present a theory of excitons in two-dimensional semiconductors using a tight-binding model of the electronic structure. In the first part, we review extensive literature on 2D van der Waals materials, with particular focus on their optical response from both experimental and theoretical points of view. In the second part, we discuss our ab initio calculations of the electronic structure of MoS2, representative of a wide class of materials, and review our minimal tight-binding model, which reproduces low-energy physics around the Fermi level and, at the same time, allows for the understanding of their electronic structure. Next, we describe how electron-hole pair excitations from the mean-field-level ground state are constructed. The electron-electron interactions mix the electron-hole pair excitations, resulting in excitonic wave functions and energies obtained by solving the Bethe-Salpeter equation. This is enabled by the efficient computation of the Coulomb matrix elements optimized for two-dimensional crystals. Next, we discuss non-local screening in various geometries usually used in experiments. We conclude with a discussion of the fine structure and excited excitonic spectra. In particular, we discuss the effect of band nesting on the exciton fine structure; Coulomb interactions; and the topology of the wave functions, screening and dielectric environment. Finally, we follow by adding another layer and discuss excitons in heterostructures built from two-dimensional semiconductors.
Collapse
Affiliation(s)
- Maciej Bieniek
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany
| | - Katarzyna Sadecka
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Ludmiła Szulakowska
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
| | - Paweł Hawrylak
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
| |
Collapse
|
25
|
Kesarwani R, Simbulan KB, Huang TD, Chiang YF, Yeh NC, Lan YW, Lu TH. Control of trion-to-exciton conversion in monolayer WS 2 by orbital angular momentum of light. SCIENCE ADVANCES 2022; 8:eabm0100. [PMID: 35363526 PMCID: PMC10938575 DOI: 10.1126/sciadv.abm0100] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Controlling the density of exciton and trion quasiparticles in monolayer two-dimensional (2D) materials at room temperature by nondestructive techniques is highly desired for the development of future optoelectronic devices. Here, the effects of different orbital angular momentum (OAM) lights on monolayer tungsten disulfide at both room temperature and low temperatures are investigated, which reveal simultaneously enhanced exciton intensity and suppressed trion intensity in the photoluminescence spectra with increasing topological charge of the OAM light. In addition, the trion-to-exciton conversion efficiency is found to increase rapidly with the OAM light at low laser power and decrease with increasing power. Moreover, the trion binding energy and the concentration of unbound electrons are estimated, which shed light on how these quantities depend on OAM. A phenomenological model is proposed to account for the experimental data. These findings pave a way toward manipulating the exciton emission in 2D materials with OAM light for optoelectronic applications.
Collapse
Affiliation(s)
- Rahul Kesarwani
- Department of Physics, National Taiwan Normal University, Taipei, Taiwan
| | | | - Teng-De Huang
- Department of Physics, National Taiwan Normal University, Taipei, Taiwan
| | - Yu-Fan Chiang
- Department of Physics, National Taiwan Normal University, Taipei, Taiwan
| | - Nai-Chang Yeh
- Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yann-Wen Lan
- Department of Physics, National Taiwan Normal University, Taipei, Taiwan
| | - Ting-Hua Lu
- Department of Physics, National Taiwan Normal University, Taipei, Taiwan
| |
Collapse
|
26
|
Fujita T, Noguchi Y. Fragment-Based Excited-State Calculations Using the GW Approximation and the Bethe-Salpeter Equation. J Phys Chem A 2021; 125:10580-10592. [PMID: 34871000 DOI: 10.1021/acs.jpca.1c07337] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we present a fragment-based approach for calculating the charged and neutral excited states in molecular systems, based on the many-body Green's function method within the GW approximation and the Bethe-Salpeter equation (BSE). The implementation relies on the many-body expansion of the total irreducible polarizability on the basis of fragment molecular orbitals. The GW quasi-particle energies in complex molecular environments are obtained by the GW calculation for the target fragment plus induced polarization contributions of the surrounding fragments at the static Coulomb-hole plus screened exchange level. In addition, we develop a large-scale GW/BSE method for calculating the delocalized excited states of molecular aggregates, based on the fragment molecular orbital method and the exciton model. The accuracy of fragment-based GW and GW/BSE methods was evaluated on molecular clusters and molecular crystals. We found that the accuracy of the total irreducible polarizability can be improved systematically by including two-body correction terms, and the fragment-based calculations can reasonably reproduce the results of the corresponding unfragmented calculations with a relative error of less than 100 meV. The proposed approach enables efficient excited-state calculations for large molecular systems with reasonable accuracy.
Collapse
Affiliation(s)
- Takatoshi Fujita
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Tokai, Ibaraki 319-1106, Japan
| | - Yoshifumi Noguchi
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University, Hamamatsu, Shizuoka 432-8561, Japan
| |
Collapse
|
27
|
Grzeszczyk M, Olkowska-Pucko K, Nogajewski K, Watanabe K, Taniguchi T, Kossacki P, Babiński A, Molas MR. Exposing the trion's fine structure by controlling the carrier concentration in hBN-encapsulated MoS 2. NANOSCALE 2021; 13:18726-18733. [PMID: 34739017 DOI: 10.1039/d1nr03855a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Atomically thin materials, like semiconducting transition metal dichalcogenides, are highly sensitive to the environment. This opens up an opportunity to externally control their properties by changing their surroundings. In this work, high-quality van der Waals heterostructures assembled from hBN-encapsulated monolayer MoS2 are studied with the aid of photoluminescence, photoluminescence excitation, and reflectance contrast experiments. We demonstrate that carrier concentration in MoS2 monolayers, arising from charge transfer from impurities in the substrate, can be significantly tuned within one order of magnitude by the modification of the bottom hBN flake thickness. The studied structures, characterized by spectral lines with linewidths approaching the narrow homogeneously broadened limit enabled observations of subtle optical and spin-valley properties of excitonic complexes. Our results allowed us to resolve three optically-active negatively charged excitons in MoS2 monolayers, which are assigned to the intravalley singlet, intervalley singlet, and intervalley triplet states.
Collapse
Affiliation(s)
- Magdalena Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Katarzyna Olkowska-Pucko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Karol Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 305-0044, Japan
| | - Piotr Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Adam Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Maciej R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| |
Collapse
|
28
|
Yue YY, Zhao LY, Han DA, Wang L, Wang HY, Gao BR, Sun HB. Trion dynamics and charge photogeneration in MoS 2 nanosheets prepared by liquid phase exfoliation. Phys Chem Chem Phys 2021; 23:22430-22436. [PMID: 34585679 DOI: 10.1039/d1cp02455h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since excitonic quasiparticles, including excitons, trions and charges, have a great influence on the photoelectric characteristics of two-dimensional (2D) transition metal dichalcogenides (TMDs), systematic explorations of the trion dynamics and charge photogeneration in 2D TMDs are important for their future optoelectronic applications. Here, broadband femtosecond transient absorption spectroscopic experiments are performed first to investigate the peak shifting and broadening kinetics in MoS2 nanosheets in solution prepared by liquid phase exfoliation (LPE-MoS2, ∼9 layers, 9L), which reveal that the binding energies for the A-, B-, and C-exciton states are ∼77 meV, ∼76 meV, and -70 meV (the energy difference between free charges and excitons; the negative sign for C-excitons means a spontaneous dissociation nature in band-nesting regions), respectively. Then, the trion dynamics and charge photogeneration in LPE-MoS2 nanosheets have been studied in detail, demonstrating that they are comparable to those in chemical vapor deposition grown MoS2 films (1L-, 3L- and 7L-MoS2). These experimental results suggest that LPE-TMD nanosheets also have the potential for use in charge-related optoelectronic devices based on 2D TMDs.
Collapse
Affiliation(s)
- Yuan-Yuan Yue
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. .,School of Management Science and Information Engineering, Jilin University of Finance and Economics, Changchun 130117, China
| | - Le-Yi Zhao
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
| | - Dan-Ao Han
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
| | - Lei Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
| | - Hai-Yu Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
| | - Bing-Rong Gao
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
| | - Hong-Bo Sun
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian, Beijing 100084, China
| |
Collapse
|
29
|
Carvalho A, Trevisanutto PE, Taioli S, Castro Neto AH. Computational methods for 2D materials modelling. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2021; 84:106501. [PMID: 34474406 DOI: 10.1088/1361-6633/ac2356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
Materials with thickness ranging from a few nanometers to a single atomic layer present unprecedented opportunities to investigate new phases of matter constrained to the two-dimensional plane. Particle-particle Coulomb interaction is dramatically affected and shaped by the dimensionality reduction, driving well-established solid state theoretical approaches to their limit of applicability. Methodological developments in theoretical modelling and computational algorithms, in close interaction with experiments, led to the discovery of the extraordinary properties of two-dimensional materials, such as high carrier mobility, Dirac cone dispersion and bright exciton luminescence, and inspired new device design paradigms. This review aims to describe the computational techniques used to simulate and predict the optical, electronic and mechanical properties of two-dimensional materials, and to interpret experimental observations. In particular, we discuss in detail the particular challenges arising in the simulation of two-dimensional constrained fermions and quasiparticles, and we offer our perspective on the future directions in this field.
Collapse
Affiliation(s)
- A Carvalho
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, 117546, Singapore
| | - P E Trevisanutto
- European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*-FBK) and Trento Institute for Fundamental Physics and Applications (TIFPA-INFN), Via Sommarive, 14, 38123 Povo TN, Trento, Italy
| | - S Taioli
- European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*-FBK) and Trento Institute for Fundamental Physics and Applications (TIFPA-INFN), Via Sommarive, 14, 38123 Povo TN, Trento, Italy
- Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia
| | - A H Castro Neto
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, 117546, Singapore
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore
| |
Collapse
|
30
|
Peimyoo N, Deilmann T, Withers F, Escolar J, Nutting D, Taniguchi T, Watanabe K, Taghizadeh A, Craciun MF, Thygesen KS, Russo S. Electrical tuning of optically active interlayer excitons in bilayer MoS 2. NATURE NANOTECHNOLOGY 2021; 16:888-893. [PMID: 34083771 DOI: 10.1038/s41565-021-00916-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Interlayer (IL) excitons, comprising electrons and holes residing in different layers of van der Waals bonded two-dimensional semiconductors, have opened new opportunities for room-temperature excitonic devices. So far, two-dimensional IL excitons have been realized in heterobilayers with type-II band alignment. However, the small oscillator strength of the resulting IL excitons and difficulties with producing heterostructures with definite crystal orientation over large areas have challenged the practical applicability of this design. Here, following the theoretical prediction and recent experimental confirmation of the existence of IL excitons in bilayer MoS2, we demonstrate the electrical control of such excitons up to room temperature. We find that the IL excitonic states preserve their large oscillator strength as their energies are manipulated by the electric field. We attribute this effect to the mixing of the pure IL excitons with intralayer excitons localized in a single layer. By applying an electric field perpendicular to the bilayer MoS2 crystal plane, excitons with IL character split into two peaks with an X-shaped field dependence as a clear fingerprint of the shift of the monolayer bands with respect to each other. Finally, we demonstrate the full control of the energies of IL excitons distributed homogeneously over a large area of our device.
Collapse
Affiliation(s)
- Namphung Peimyoo
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Thorsten Deilmann
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Freddie Withers
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Janire Escolar
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Darren Nutting
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Alireza Taghizadeh
- Department of Materials and Production, Aalborg University, Aalborg, Denmark
- CAMD, Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Monica Felicia Craciun
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Kristian Sommer Thygesen
- CAMD, Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Saverio Russo
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK.
| |
Collapse
|
31
|
Chang YW, Chang YC. Variationally optimized orbital approach to trions in two-dimensional materials. J Chem Phys 2021; 155:024110. [PMID: 34266270 DOI: 10.1063/5.0057493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, trions in two-dimensional (2D) space are studied by the variational method with trial wavefunctions being constructed by 2D slater-type orbitals. Via this method, trion energy levels and wavefunctions can be calculated efficiently with fairly good accuracy. We first apply this method to study trion energy levels in a 2D hydrogen-like system with respect to a wide range of mass ratios and screening lengths. We find that the ground-state trion is bound for the whole parameter range, and an excited-state trion with antisymmetric permutation of electrons with finite angular momentum is bound for large electron-hole mass ratios or long screening lengths. The binding energies of ground-state trions calculated by the present method agree well with those calculated by more sophisticated but computationally demanding methods. We then calculate trion binding energies in various monolayer transition metal dichalcogenides (TMDCs) by using this method with the inclusion of electron-hole exchange (EHX) interaction. For TMDCs, we found that the effect of EHX can be significant in determining the trion binding energy and the possible existence of stable excited-state trions.
Collapse
Affiliation(s)
- Yao-Wen Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Yia-Chung Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| |
Collapse
|
32
|
Park S, Wang H, Schultz T, Shin D, Ovsyannikov R, Zacharias M, Maksimov D, Meissner M, Hasegawa Y, Yamaguchi T, Kera S, Aljarb A, Hakami M, Li L, Tung V, Amsalem P, Rossi M, Koch N. Temperature-Dependent Electronic Ground-State Charge Transfer in van der Waals Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008677. [PMID: 34032324 PMCID: PMC11468622 DOI: 10.1002/adma.202008677] [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: 12/23/2020] [Revised: 04/03/2021] [Indexed: 06/12/2023]
Abstract
Electronic charge rearrangement between components of a heterostructure is the fundamental principle to reach the electronic ground state. It is acknowledged that the density of state distribution of the components governs the amount of charge transfer, but a notable dependence on temperature is not yet considered, particularly for weakly interacting systems. Here, it is experimentally observed that the amount of ground-state charge transfer in a van der Waals heterostructure formed by monolayer MoS2 sandwiched between graphite and a molecular electron acceptor layer increases by a factor of 3 when going from 7 K to room temperature. State-of-the-art electronic structure calculations of the full heterostructure that accounts for nuclear thermal fluctuations reveal intracomponent electron-phonon coupling and intercomponent electronic coupling as the key factors determining the amount of charge transfer. This conclusion is rationalized by a model applicable to multicomponent van der Waals heterostructures.
Collapse
Affiliation(s)
- Soohyung Park
- Advanced Analysis CenterKorea Institute of Science and Technology (KIST)Seoul02792South Korea
| | - Haiyuan Wang
- Fritz Haber Institute of the Max Planck Society14195BerlinGermany
- Chaire de Simulation à l'Echelle Atomique (CSEA)Ecole Polytechnique Fédérale de Lausanne (EPFL)LausanneCH‐1015Switzerland
| | - Thorsten Schultz
- Humboldt‐Universität zu BerlinInstitut für Physik and IRIS Adlershof12489BerlinGermany
- Helmholtz‐Zentrum für Materialien und Energie GmbH12489BerlinGermany
| | - Dongguen Shin
- Humboldt‐Universität zu BerlinInstitut für Physik and IRIS Adlershof12489BerlinGermany
| | | | - Marios Zacharias
- Fritz Haber Institute of the Max Planck Society14195BerlinGermany
- Department of Mechanical and Materials Science EngineeringCyprus University of TechnologyLimassol3603Cyprus
| | - Dmitrii Maksimov
- Fritz Haber Institute of the Max Planck Society14195BerlinGermany
- Max Planck Institute for the Structure and Dynamics of Matter22761HamburgGermany
| | | | | | | | - Satoshi Kera
- Institute for Molecular ScienceOkazaki444‐8585Japan
| | - Areej Aljarb
- Physical Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwal23955‐6900Saudi Arabia
| | - Mariam Hakami
- Physical Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwal23955‐6900Saudi Arabia
| | - Lain‐Jong Li
- Physical Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwal23955‐6900Saudi Arabia
- Department of Mechanical EngineeringThe University of Hong KongPok Fu Lam RoadHong KongChina
| | - Vincent Tung
- Physical Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwal23955‐6900Saudi Arabia
| | - Patrick Amsalem
- Humboldt‐Universität zu BerlinInstitut für Physik and IRIS Adlershof12489BerlinGermany
| | - Mariana Rossi
- Fritz Haber Institute of the Max Planck Society14195BerlinGermany
- Max Planck Institute for the Structure and Dynamics of Matter22761HamburgGermany
| | - Norbert Koch
- Humboldt‐Universität zu BerlinInstitut für Physik and IRIS Adlershof12489BerlinGermany
- Helmholtz‐Zentrum für Materialien und Energie GmbH12489BerlinGermany
| |
Collapse
|
33
|
Heißenbüttel MC, Deilmann T, Krüger P, Rohlfing M. Valley-Dependent Interlayer Excitons in Magnetic WSe 2/CrI 3. NANO LETTERS 2021; 21:5173-5178. [PMID: 34077218 DOI: 10.1021/acs.nanolett.1c01232] [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
Heterostructures of two-dimensional transition-metal dichalcogenides and ferromagnetic substrates are important candidates for the development of viable new spin- or valleytronic devices. For the prototypical bilayer of WSe2 on top of a ferromagnetic layer of CrI3, we find substantially different coupling of both WSe2 K-valleys to the sublayer. Besides an energy splitting of a few meV, the corresponding excitons have significantly different interlayer character with charge transfer allowed at the K̅- point but forbidden at K̅+. The different exciton wave functions result in a distinctly different response to magnetic fields with g factors of about -4.4 and -4.0, respectively. By means of ab initio GW/Bethe-Salpeter equation calculations, these findings establish g factors as tool for investigating the exciton character and shedding light on the detailed quantum-mechanical interplay of magnetic and optical properties which are essential for the targeted development of optoelectronic devices.
Collapse
Affiliation(s)
| | - Thorsten Deilmann
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Peter Krüger
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Michael Rohlfing
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| |
Collapse
|
34
|
Xie K, Li X, Cao T. Theory and Ab Initio Calculation of Optically Excited States-Recent Advances in 2D Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e1904306. [PMID: 31808581 DOI: 10.1002/adma.201904306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/19/2019] [Indexed: 05/16/2023]
Abstract
Recent studies of the optical properties of 2D materials have reported unique phenomena and features that are absent in conventional bulk semiconductors. Many of these interesting properties, such as enhanced light-matter coupling, gate-tunable photoluminescence, and unusual excitonic optical selection rules arise from the nature of the two- and multi-particle excited states such as strongly bound Wannier excitons and charged excitons. The theory, modeling, and ab initio calculations of these optically excited states in 2D materials are reviewed. Several analytical and ab initio approaches are introduced. These methods are compared with each other, revealing their relative strength and limitations. Recent works that apply these methods to a variety of 2D materials and material-defect systems are then highlighted. Understanding of the optically excited states in these systems is relevant not only for fundamental scientific research of electronic excitations and correlations, but also plays an important role in the future development of quantum information science and nano-photonics.
Collapse
Affiliation(s)
- Kaichen Xie
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Xiaosong Li
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
| |
Collapse
|
35
|
Sebait R, Biswas C, Song B, Seo C, Lee YH. Identifying Defect-Induced Trion in Monolayer WS 2 via Carrier Screening Engineering. ACS NANO 2021; 15:2849-2857. [PMID: 33470093 DOI: 10.1021/acsnano.0c08828] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Unusually high exciton binding energies (BEs), as much as ∼1 eV in monolayer transition-metal dichalcogenides, provide opportunities for exploring exotic and stable excitonic many-body effects. These include many-body neutral excitons, trions, biexcitons, and defect-induced excitons at room temperature, rarely realized in bulk materials. Nevertheless, the defect-induced trions correlated with charge screening have never been observed, and the corresponding BEs remain unknown. Here we report defect-induced A-trions and B-trions in monolayer tungsten disulfide (WS2) via carrier screening engineering with photogenerated carrier modulation, external doping, and substrate scattering. Defect-induced trions strongly couple with inherent SiO2 hole traps under high photocarrier densities and become more prominent in rhenium-doped WS2. The absence of defect-induced trion peaks was confirmed using a trap-free hexagonal boron nitride substrate, regardless of power density. Moreover, many-body excitonic charge states and their BEs were compared via carrier screening engineering at room temperature. The highest BE was observed in the defect-induced A-trion state (∼214 meV), comparably higher than the trion (209 meV) and neutral exciton (174 meV), and further tuned by external photoinduced carrier density control. This investigation allows us to demonstrate defect-induced trion BE localization via spatial BE mapping in the monolayer WS2 midflake regions distinctive from the flake edges.
Collapse
|
36
|
Giant nonlinear optical activity in two-dimensional palladium diselenide. Nat Commun 2021; 12:1083. [PMID: 33597512 PMCID: PMC7889859 DOI: 10.1038/s41467-021-21267-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/15/2021] [Indexed: 11/15/2022] Open
Abstract
Nonlinear optical effects in layered two-dimensional transition metal chalcogenides have been extensively explored recently because of the promising prospect of the nonlinear optical effects for various optoelectronic applications. However, these materials possess sizable bandgaps ranging from visible to ultraviolet region, so the investigation of narrow-bandgap materials remains deficient. Here, we report our comprehensive study on the nonlinear optical processes in palladium diselenide (PdSe2) that has a near-infrared bandgap. Interestingly, this material exhibits a unique thickness-dependent second harmonic generation feature, which is in contrast to other transition metal chalcogenides. Furthermore, the two-photon absorption coefficients of 1–3 layer PdSe2 (β ~ 4.16 × 105, 2.58 × 105, and 1.51 × 105 cm GW−1) are larger by two and three orders of magnitude than that of the conventional two-dimensional materials, and giant modulation depths (αs ~ 32%, 27%, and 24%) were obtained in 1–3 layer PdSe2. Such unique nonlinear optical characteristics make PdSe2 a potential candidate for technological innovations in nonlinear optoelectronic devices. Strong nonlinearities in 2D materials can lead to interesting applications in optoelectronics. Here the authors investigate the optical nonlinearity of palladium diselenide, determine the layer dependent two photon absorption efficiency and the saturable absorption modulation depth.
Collapse
|
37
|
Jadczak J, Kutrowska-Girzycka J, Bieniek M, Kazimierczuk T, Kossacki P, Schindler JJ, Debus J, Watanabe K, Taniguchi T, Ho CH, Wójs A, Hawrylak P, Bryja L. Probing negatively charged and neutral excitons in MoS 2/hBN and hBN/MoS 2/hBN van der Waals heterostructures. NANOTECHNOLOGY 2021; 32:145717. [PMID: 33463532 DOI: 10.1088/1361-6528/abd507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
High-quality van der Waals heterostructures assembled from hBN-encapsulated monolayer transition metal dichalcogenides enable observations of subtle optical and spin-valley properties whose identification was beyond the reach of structures exfoliated directly on standard SiO2/Si substrates. Here, we describe different van der Waals heterostructures based on uncapped single-layer MoS2 stacked onto hBN layers of different thicknesses and hBN-encapsulated monolayers. Depending on the doping level, they reveal the fine structure of excitonic complexes, i.e. neutral and charged excitons. In the emission spectra of a particular MoS2/hBN heterostructure without an hBN cap we resolve two trion peaks, T1 and T2, energetically split by about 10 meV, resembling the pair of singlet and triplet trion peaks (T S and T T ) in tungsten-based materials. The existence of these trion features suggests that monolayer MoS2 has a dark excitonic ground state, despite having a 'bright' single-particle arrangement of spin-polarized conduction bands. In addition, we show that the effective excitonic g-factor significantly depends on the electron concentration and reaches the lowest value of -2.47 for hBN-encapsulated structures, which reveals a nearly neutral doping regime. In the uncapped MoS2 structures, the excitonic g-factor varies from -1.15 to -1.39 depending on the thickness of the bottom hBN layer and decreases as a function of rising temperature.
Collapse
Affiliation(s)
- J Jadczak
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Zhang Y, Shinokita K, Watanabe K, Taniguchi T, Goto M, Kan D, Shimakawa Y, Moritomo Y, Nishihara T, Miyauchi Y, Matsuda K. Controllable Magnetic Proximity Effect and Charge Transfer in 2D Semiconductor and Double-Layered Perovskite Manganese Oxide van der Waals Heterostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003501. [PMID: 33118213 DOI: 10.1002/adma.202003501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/30/2020] [Indexed: 05/27/2023]
Abstract
Optically generated excitonic states (excitons and trions) in transition metal dichalcogenides are highly sensitive to the electronic and magnetic properties of the materials underneath. Modulation and control of the excitonic states in a novel van der Waals (vdW) heterostructure of monolayer MoSe2 on double-layered perovskite Mn oxide ((La0.8 Nd0.2 )1.2 Sr1.8 Mn2 O7 ) is demonstrated, wherein the Mn oxide transforms from a paramagnetic insulator to a ferromagnetic metal. A discontinuous change in the exciton photoluminescence intensity via dielectric screening is observed. Further, a relatively high trion intensity is discovered due to the charge transfer from metallic Mn oxide under the Curie temperature. Moreover, the vdW heterostructures with an ultrathin h-BN spacer layer demonstrate enhanced valley splitting and polarization of excitonic states due to the proximity effect of the ferromagnetic spins of Mn oxide. The controllable h-BN thickness in vdW heterostructures reveals a several-nanometer-long scale of charge transfer as well as a magnetic proximity effect. The vdW heterostructure allows modulation and control of the excitonic states via dielectric screening, charge carriers, and magnetic spins.
Collapse
Affiliation(s)
- Yan Zhang
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Keisuke Shinokita
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Masato Goto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Daisuke Kan
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yuichi Shimakawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yutaka Moritomo
- Graduate School of Pure & Applied Science and Faculty of Pure & Applied Science, University of Tsukuba, Tsukuba, Ibaraki, 305-7571, Japan
| | - Taishi Nishihara
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yuhei Miyauchi
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Kazunari Matsuda
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011, Japan
| |
Collapse
|
39
|
Lyons TP, Gillard D, Molina-Sánchez A, Misra A, Withers F, Keatley PS, Kozikov A, Taniguchi T, Watanabe K, Novoselov KS, Fernández-Rossier J, Tartakovskii AI. Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe 2/CrBr 3 van der Waals heterostructures. Nat Commun 2020; 11:6021. [PMID: 33244001 PMCID: PMC7691354 DOI: 10.1038/s41467-020-19816-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 10/30/2020] [Indexed: 11/18/2022] Open
Abstract
Semiconducting ferromagnet-nonmagnet interfaces in van der Waals heterostructures present a unique opportunity to investigate magnetic proximity interactions dependent upon a multitude of phenomena including valley and layer pseudospins, moiré periodicity, or exceptionally strong Coulomb binding. Here, we report a charge-state dependency of the magnetic proximity effects between MoSe2 and CrBr3 in photoluminescence, whereby the valley polarization of the MoSe2 trion state conforms closely to the local CrBr3 magnetization, while the neutral exciton state remains insensitive to the ferromagnet. We attribute this to spin-dependent interlayer charge transfer occurring on timescales between the exciton and trion radiative lifetimes. Going further, we uncover by both the magneto-optical Kerr effect and photoluminescence a domain-like spatial topography of contrasting valley polarization, which we infer to be labyrinthine or otherwise highly intricate, with features smaller than 400 nm corresponding to our optical resolution. Our findings offer a unique insight into the interplay between short-lived valley excitons and spin-dependent interlayer tunneling, while also highlighting MoSe2 as a promising candidate to optically interface with exotic spin textures in van der Waals structures.
Collapse
Affiliation(s)
- T P Lyons
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK.
| | - D Gillard
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - A Molina-Sánchez
- QuantaLab, International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - A Misra
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
- Department of Physics, Indian Institute of Technology Madras (IIT Madras), Chennai, India
| | - F Withers
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - P S Keatley
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - A Kozikov
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - K S Novoselov
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore
- Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing, 400714, China
| | - J Fernández-Rossier
- QuantaLab, International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - A I Tartakovskii
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK.
| |
Collapse
|
40
|
Zhumagulov YV, Vagov A, Gulevich DR, Faria Junior PE, Perebeinos V. Trion induced photoluminescence of a doped MoS2 monolayer. J Chem Phys 2020; 153:044132. [DOI: 10.1063/5.0012971] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yaroslav V. Zhumagulov
- ITMO University, St. Petersburg 197101, Russia
- University of Regensburg, Regensburg 93040, Germany
| | | | | | | | - Vasili Perebeinos
- ITMO University, St. Petersburg 197101, Russia
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| |
Collapse
|
41
|
Zhang D, Gan L, Zhang J, Zhang R, Wang Z, Feng J, Sun H, Ning CZ. Reconstructing Local Profile of Exciton-Emission Wavelengths across a WS 2 Bubble beyond the Diffraction Limit. ACS NANO 2020; 14:6931-6937. [PMID: 32491830 DOI: 10.1021/acsnano.0c01337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Air bubbles formed between layers of two-dimensional (2D) materials not only are unavoidable but also emerge as an important means of engineering their excitonic emission properties, especially as controllable quantum light sources. Measuring the actual spatially resolved optical properties across such bubbles is important for understanding excitonic physics and for device applications; however, such a measurement is challenging due to nanoscale features involved which require spatial resolution beyond the diffraction limit. Additional complexity is the involvement of multiple physical effects such as mechanical strain and dielectric environment that are difficult to disentangle. In this paper, we demonstrate an effective approach combining micro-photoluminescence measurement, atomic force microscope profile mapping, and a theoretical strain model. We succeeded in reconstructing the actual spatial profiles of the emission wavelengths beyond the diffraction limit for bubbles formed by a monolayer tungsten disulfide on boron nitride. The agreements and consistency among various approaches established the validity of our approach. In addition, our approach allows us to disentangle the effects of strain and dielectric environment and provides a general and reliable method to determine the true magnitude of wavelength changes due to the individual effects across bubbles. Importantly, we found that micro-optical measurement underestimates the red and blue shifts by almost 5 times. Our results provide important insights into strain and screening-dependent optical properties of 2D materials on the nanometer scale and contribute significantly to our understanding of excitonic emission physics as well as potential applications of bubbles in optoelectronic devices.
Collapse
Affiliation(s)
- Danyang Zhang
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
| | - Lin Gan
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
- Beijing National Research Center for Information Science and Technology, Beijing 100084, China
| | - Jianxing Zhang
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
| | - Ruiling Zhang
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
| | - Zhen Wang
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
| | - Jiabin Feng
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
| | - Hao Sun
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
- Beijing National Research Center for Information Science and Technology, Beijing 100084, China
| | - Cun-Zheng Ning
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
- International Center for Nano-Optoelectronics, Tsinghua University, Beijing 100084, China
- Beijing National Research Center for Information Science and Technology, Beijing 100084, China
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287, United States
| |
Collapse
|
42
|
Deilmann T, Krüger P, Rohlfing M. Ab Initio Studies of Exciton g Factors: Monolayer Transition Metal Dichalcogenides in Magnetic Fields. PHYSICAL REVIEW LETTERS 2020; 124:226402. [PMID: 32567922 DOI: 10.1103/physrevlett.124.226402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
The effect of a magnetic field on the optical absorption in semiconductors has been measured experimentally and modeled theoretically for various systems in previous decades. We present a new first-principles approach to systematically determine the response of excitons to magnetic fields, i.e., exciton g factors. By utilizing the GW-Bethe-Salpeter equation methodology we show that g factors extracted from the Zeeman shift of electronic bands are strongly renormalized by many-body effects which we trace back to the extent of the excitons in reciprocal space. We apply our approach to monolayers of transition metal dichalcogenides (MoS_{2}, MoSe_{2}, MoTe_{2}, WS_{2}, and WSe_{2}) with strongly bound excitons for which g factors are weakened by about 30%.
Collapse
Affiliation(s)
- Thorsten Deilmann
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Peter Krüger
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Michael Rohlfing
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| |
Collapse
|
43
|
Deilmann T, Rohlfing M, Wurstbauer U. Light-matter interaction in van der Waals hetero-structures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:333002. [PMID: 32244237 DOI: 10.1088/1361-648x/ab8661] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Even if individual two-dimensional materials own various interesting and unexpected properties, the stacking of such layers leads to van der Waals solids which unite the characteristics of two dimensions with novel features originating from the interlayer interactions. In this topical review, we cover fabrication and characterization of van der Waals hetero-structures with a focus on hetero-bilayers made of monolayers of semiconducting transition metal dichalcogenides. Experimental and theoretical techniques to investigate those hetero-bilayers are introduced. Most recent findings focusing on different transition metal dichalcogenides hetero-structures are presented and possible optical transitions between different valleys, appearance of moiré patterns and signatures of moiré excitons are discussed. The fascinating and fast growing research on van der Waals hetero-bilayers provide promising insights required for their application as emerging quantum-nano materials.
Collapse
Affiliation(s)
- Thorsten Deilmann
- Institut für Festkörertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str.10, 48149 Münster, Germany
| | - Michael Rohlfing
- Institut für Festkörertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str.10, 48149 Münster, Germany
| | - Ursula Wurstbauer
- Institute of Physics, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str.10, 48149 Münster, Germany
| |
Collapse
|
44
|
Greben K, Arora S, Harats MG, Bolotin KI. Intrinsic and Extrinsic Defect-Related Excitons in TMDCs. NANO LETTERS 2020; 20:2544-2550. [PMID: 32191482 DOI: 10.1021/acs.nanolett.9b05323] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We investigate the excitonic peak associated with defects and disorder in low-temperature photoluminescence of monolayer transition metal dichalcogenides (TMDCs). To uncover the intrinsic origin of defect-related (D) excitons, we study their dependence on gate voltage, excitation power, and temperature in a prototypical TMDC monolayer MoS2. Our results suggest that D excitons are neutral excitons bound to ionized donor levels, likely related to sulfur vacancies, with a density of 7 × 1011 cm-2. To study the extrinsic contribution to D excitons, we controllably deposit oxygen molecules in situ onto the surface of MoS2 kept at cryogenic temperature. We find that, in addition to trivial p-doping of 3 × 1012 cm-2, oxygen affects the D excitons, likely by functionalizing the defect sites. Combined, our results uncover the origin of D excitons, suggest an approach to track the functionalization of TMDCs, to benchmark device quality, and pave the way toward exciton engineering in hybrid organic-inorganic TMDC devices.
Collapse
Affiliation(s)
- Kyrylo Greben
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Sonakshi Arora
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Moshe G Harats
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Kirill I Bolotin
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| |
Collapse
|
45
|
Das T, Datta S. Thermochemical stability, and electronic and dielectric properties of Janus bismuth oxyhalide BiOX (X = Cl, Br, I) monolayers. NANOSCALE ADVANCES 2020; 2:1090-1104. [PMID: 36133068 PMCID: PMC9417667 DOI: 10.1039/c9na00750d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/06/2020] [Indexed: 06/11/2023]
Abstract
Ultrathin monolayers of bismuth oxyhalide materials BiOX (X = Cl, Br, I) grown along 〈001〉 are studied using first-principles density functional theory. Both pristine BiOX and Janus (X, X' = Cl, Br, I) monolayers are investigated by analyzing their structural stability using formation enthalpy and phonon density of states. On the other hand, their thermochemical reactivity is understood from their surface energy trends in symmetric and asymmetric terminations. The theoretically measured optical band gaps and fundamental band gaps of these Janus monolayers are compared with their pristine counterparts BiOX and BiOX' as well as to the known experimental measurements. All of the possible Janus monolayers possess structural, electronic and optical properties intermediate to the corresponding properties of the two associated pristine BiOX and BiOX' monolayers. According to the formation enthalpy, stabilization is equally favorable for all the monolayers, whereas the lowest surface energy is found for BiOCl0.5Br0.5, leading to excellent thermochemical reactivity which is consistent with recent experimental measurements. The frequency dependent dielectric functions are simulated in the density functional perturbation theory limit, and the optical band gaps are estimated from the absorption and reflectance spectra, and are in excellent agreement with the known experimentally measured values. High frequency dielectric constants of these materials with 2D symmetry are estimated from G 0 W 0 calculations including local field and spin-orbit effects. The larger dielectric constants and wider differences in the charge carriers' effective masses also provide proof that this new class of 2D materials has potential in photo-electrochemical applications. Thus, fabricating Janus monolayers of these oxyhalide compounds would open up a rational design strategy for tailoring their optoelectronic properties, which may offer guidance for the design of highly efficient optoelectronic materials for catalysis, valleytronic, and sensing applications.
Collapse
Affiliation(s)
- Tilak Das
- Università degli Studi Milano-Bicocca, Dipartimento di Scienza dei Materiali via R. Cozzi, 55 Milano - 20125 Italy
| | - Soumendu Datta
- Department of Condensed Matter Physics and Material Sciences, Satyendra Nath Bose National Centre for Basic Sciences JD Block, Sector-III, Salt Lake City Kolkata - 700 106 India
| |
Collapse
|
46
|
Arora A, Deilmann T, Reichenauer T, Kern J, Michaelis de Vasconcellos S, Rohlfing M, Bratschitsch R. Excited-State Trions in Monolayer WS_{2}. PHYSICAL REVIEW LETTERS 2019; 123:167401. [PMID: 31702327 DOI: 10.1103/physrevlett.123.167401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Indexed: 05/16/2023]
Abstract
We discover an excited bound three-particle state, the 2s trion, appearing energetically below the 2s exciton in monolayer WS_{2}, using absorption spectroscopy and ab initio GW and Bethe-Salpeter equation calculations. The measured binding energy of the 2s trion (22 meV) is smaller compared to the 1s intravalley and intervalley trions (37 and 31 meV). With increasing temperature, the 1s and 2s trions transfer their oscillator strengths to the respective neutral excitons, establishing an optical fingerprint of trion-exciton resonance pairs. Our discovery underlines the importance of trions for the entire excitation spectrum of two-dimensional semiconductors.
Collapse
Affiliation(s)
- Ashish Arora
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Thorsten Deilmann
- Institute of Solid State Theory, Wilhelm-Klemm-Straße 10, University of Münster, 48149 Münster, Germany
| | - Till Reichenauer
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Johannes Kern
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | | | - Michael Rohlfing
- Institute of Solid State Theory, Wilhelm-Klemm-Straße 10, University of Münster, 48149 Münster, Germany
| | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| |
Collapse
|
47
|
He Z, Han Z, Yuan J, Sinyukov AM, Eleuch H, Niu C, Zhang Z, Lou J, Hu J, Voronine DV, Scully MO. Quantum plasmonic control of trions in a picocavity with monolayer WS 2. SCIENCE ADVANCES 2019; 5:eaau8763. [PMID: 31646171 PMCID: PMC6788863 DOI: 10.1126/sciadv.aau8763] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/14/2019] [Indexed: 05/30/2023]
Abstract
Monitoring and controlling the neutral and charged excitons (trions) in two-dimensional (2D) materials are essential for the development of high-performance devices. However, nanoscale control is challenging because of diffraction-limited spatial resolution of conventional far-field techniques. Here, we extend the classical tip-enhanced photoluminescence based on tip-substrate nanocavity to quantum regime and demonstrate controlled nano-optical imaging, namely, tip-enhanced quantum plasmonics. In addition to improving the spatial resolution, we use the scanning probe to control the optoelectronic response of monolayer WS2 by varying the neutral/charged exciton ratio via charge tunneling in Au-Ag picocavity. We observe trion "hot spots" generated by varying the picometer-scale probe-sample distance and show the effects of weak and strong coupling, which depend on the spatial location. Our experimental results are in agreement with simulations and open an unprecedented view of a new range of quantum plasmonic phenomena with 2D materials that will help to design new quantum optoelectronic devices.
Collapse
Affiliation(s)
- Zhe He
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Zehua Han
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Jiangtan Yuan
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
| | - Alexander M. Sinyukov
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Hichem Eleuch
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843, USA
- Department of Applied Sciences and Mathematics, College of Arts and Sciences, Abu Dhabi University, Abu Dhabi, United Arab Emirates
| | - Chao Niu
- Baylor Research and Innovation Collaborative, Baylor University, Waco, TX 76798, USA
- Department of Electrical and Computer Engineering, Baylor University, Waco, TX 76798, USA
| | - Zhenrong Zhang
- Baylor Research and Innovation Collaborative, Baylor University, Waco, TX 76798, USA
- Department of Physics, Baylor University, Waco, TX 76798, USA
| | - Jun Lou
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
| | - Jonathan Hu
- Baylor Research and Innovation Collaborative, Baylor University, Waco, TX 76798, USA
- Department of Electrical and Computer Engineering, Baylor University, Waco, TX 76798, USA
| | - Dmitri V. Voronine
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Marlan O. Scully
- Institute for Quantum Science and Engineering, Texas A&M University, College Station, TX 77843, USA
- Baylor Research and Innovation Collaborative, Baylor University, Waco, TX 76798, USA
| |
Collapse
|
48
|
Tempelaar R, Berkelbach TC. Many-body simulation of two-dimensional electronic spectroscopy of excitons and trions in monolayer transition metal dichalcogenides. Nat Commun 2019; 10:3419. [PMID: 31366945 PMCID: PMC6668418 DOI: 10.1038/s41467-019-11497-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 07/16/2019] [Indexed: 12/02/2022] Open
Abstract
Indications of coherently interacting excitons and trions in doped transition metal dichalcogenides have been measured as quantum beats in two-dimensional electronic spectroscopy, but the microscopic principles underlying the optical signals of exciton-trion coherence remain to be clarified. Here we present calculations of two-dimensional spectra of such monolayers based on a microscopic many-body formalism. We use a parameterized band structure and a static model dielectric function, although a full ab initio implementation of our formalism is possible in principle. Our simulated spectra are in excellent agreement with experiments, including the quantum beats, while revealing the interplay between excitons and trions in molybdenum- and tungsten-based transition metal dichalcogenides. Quantum beats are confirmed to unambiguously reflect the exciton-trion coherence time in molybdenum compounds, but are shown to provide a lower bound to the coherence time for tungsten analogues due to a destructive interference from coexisting singlet and triplet trions. 2D electronic spectroscopy found experimental indications of coherently interacting excitons and trions in doped transition metal dichalcogenides (TMDCs). Here, the authors perform simulations of 2D spectra of monolayer TMDCs based on a many-body formalism, allowing to relate exciton-trion coherence to quantum beats based on microscopic principles.
Collapse
Affiliation(s)
- Roel Tempelaar
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.
| | - Timothy C Berkelbach
- Department of Chemistry, Columbia University, New York, NY, 10027, USA. .,Center for Computational Quantum Physics, Flatiron Institute, New York, NY, 10010, USA.
| |
Collapse
|
49
|
Ulstrup S, Giusca CE, Miwa JA, Sanders CE, Browning A, Dudin P, Cacho C, Kazakova O, Gaskill DK, Myers-Ward RL, Zhang T, Terrones M, Hofmann P. Nanoscale mapping of quasiparticle band alignment. Nat Commun 2019; 10:3283. [PMID: 31337765 PMCID: PMC6650412 DOI: 10.1038/s41467-019-11253-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/02/2019] [Indexed: 11/22/2022] Open
Abstract
Control of atomic-scale interfaces between materials with distinct electronic structures is crucial for the design and fabrication of most electronic devices. In the case of two-dimensional materials, disparate electronic structures can be realized even within a single uniform sheet, merely by locally applying different vertical gate voltages. Here, we utilize the inherently nano-structured single layer and bilayer graphene on silicon carbide to investigate lateral electronic structure variations in an adjacent single layer of tungsten disulfide (WS2). The electronic band alignments are mapped in energy and momentum space using angle-resolved photoemission with a spatial resolution on the order of 500 nm (nanoARPES). We find that the WS2 band offsets track the work function of the underlying single layer and bilayer graphene, and we relate such changes to observed lateral patterns of exciton and trion luminescence from WS2. Sharp atomic interfaces between materials dictate the interface’s electronic properties. The authors use angle-resolved photoemission spectroscopy with a spatial resolution of ~500 nm to investigate the nanoscale electronic band structure and band alignment in a lateral heterostructure composed of WS2 placed on alternating nano-stripes of monolayer and bilayer graphene.
Collapse
Affiliation(s)
- Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark.
| | - Cristina E Giusca
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK.
| | - Jill A Miwa
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
| | - Charlotte E Sanders
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Alex Browning
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Pavel Dudin
- Diamond Light Source, Division of Science, Didcot, OX11 0DE, UK
| | - Cephise Cacho
- Diamond Light Source, Division of Science, Didcot, OX11 0DE, UK
| | - Olga Kazakova
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - D Kurt Gaskill
- U.S. Naval Research Laboratory, Washington, DC, 20375, USA
| | | | - Tianyi Zhang
- Department of Physics and Center for 2-Dimensional and Layered Materials, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mauricio Terrones
- Department of Physics and Center for 2-Dimensional and Layered Materials, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
| |
Collapse
|
50
|
Pang H, Huang P, Zhuo W, Li M, Gao C, Guo D. Hysteresis and its impact on characterization of mechanical properties of suspended monolayer molybdenum-disulfide sheets. Phys Chem Chem Phys 2019; 21:7454-7461. [PMID: 30892298 DOI: 10.1039/c8cp07158f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The hysteresis phenomenon frequently arises in two-dimensional (2D) material nanoindentation, which is generally expected to be excluded from characterizing the elastic properties due to the imperfect elastic behaviour. However, the underlying mechanism of hysteresis and its effect on the characterization of the mechanical properties of 2D materials remain unclear. Cyclic loadings are exerted on the suspended monolayer molybdenum-disulfide (MoS2) films in atomic force microscopy (AFM) nanoindentation experiments. The elastic hysteresis loops are observed for most of the force-displacement curves. The friction/wear between the AFM silicon tip and the MoS2 monolayer is deemed to be dominant compared to the friction between the monolayer and the silicon dioxide substrate after the analysis, as determined using the finite element method (FEM) simulation. The loading force-displacement curves instead of the unloading curves have been used to deduce the elastic mechanical properties using a modified regression equation. The mean value of the obtained Young's modulus of monolayer MoS2, E, is equal to 209 ± 18 GPa, which is close to the inherent stiffness value, predicted by first principles calculation. Our results have confirmed that it is not obligatory to exclude the sample data with hysteresis behaviour for characterizing the elastic properties of 2D materials. In addition, all sample sheets have finally been penetrated and the mean breaking stress value, σmax, is 36.6 ± 0.9 GPa, determined using the radius value of the worn tip. Furthermore, the effect of the loading force and the shape/size of the suspended monolayer MoS2 sheets on the hysteresis behaviour in the 2D nanoindentation have also been analyzed and discussed, exhibiting interesting trends. Our findings provide guidance for the characterization of the mechanical properties of 2D materials using the AFM nanoindentation and the experimental samples with elastic hysteresis behaviour.
Collapse
Affiliation(s)
- Haosheng Pang
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, Fujian, China.
| | | | | | | | | | | |
Collapse
|