1
|
Cheng B, Cheng D, Jiang T, Xia W, Song B, Mootz M, Luo L, Perakis IE, Yao Y, Guo Y, Wang J. Chirality manipulation of ultrafast phase switches in a correlated CDW-Weyl semimetal. Nat Commun 2024; 15:785. [PMID: 38278821 PMCID: PMC10817907 DOI: 10.1038/s41467-024-45036-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024] Open
Abstract
Light engineering of correlated states in topological materials provides a new avenue of achieving exotic topological phases inaccessible by conventional tuning methods. Here we demonstrate a light control of correlation gaps in a model charge-density-wave (CDW) and polaron insulator (TaSe4)2I recently predicted to be an axion insulator. Our ultrafast terahertz photocurrent spectroscopy reveals a two-step, non-thermal melting of polarons and electronic CDW gap via the fluence dependence of a longitudinal circular photogalvanic current. This helicity-dependent photocurrent reveals continuous ultrafast phase switches from the polaronic state to the CDW (axion) phase, and finally to a hidden Weyl phase as the pump fluence increases. Additional distinctive attributes aligning with the light-induced switches include: the mode-selective coupling of coherent phonons to the polaron and CDW modulation, and the emergence of a non-thermal chiral photocurrent above the pump threshold of CDW-related phonons. The demonstrated ultrafast chirality control of correlated topological states here holds large potentials for realizing axion electrodynamics and advancing quantum-computing applications.
Collapse
Affiliation(s)
- Bing Cheng
- Ames National Laboratory, Ames, IA, 50011, USA.
| | - Di Cheng
- Ames National Laboratory, Ames, IA, 50011, USA
| | - Tao Jiang
- Ames National Laboratory, Ames, IA, 50011, USA
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 201210, China
| | - Boqun Song
- Ames National Laboratory, Ames, IA, 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - Martin Mootz
- Ames National Laboratory, Ames, IA, 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - Liang Luo
- Ames National Laboratory, Ames, IA, 50011, USA
| | - Ilias E Perakis
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL, 35294-1170, USA
| | - Yongxin Yao
- Ames National Laboratory, Ames, IA, 50011, USA
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 201210, China
| | - Jigang Wang
- Ames National Laboratory, Ames, IA, 50011, USA.
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA.
| |
Collapse
|
2
|
Kim RHJ, Pathak AK, Park JM, Imran M, Haeuser SJ, Fei Z, Mudryk Y, Koschny T, Wang J. Nano-compositional imaging of the lanthanum silicide system at THz wavelengths. OPTICS EXPRESS 2024; 32:2356-2363. [PMID: 38297768 DOI: 10.1364/oe.507414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/12/2023] [Indexed: 02/02/2024]
Abstract
Terahertz scattering-type scanning near-field optical microscopy (THz-sSNOM) provides a noninvasive way to probe the low frequency conductivity of materials and to characterize material compositions at the nanoscale. However, the potential capability of atomic compositional analysis with THz nanoscopy remains largely unexplored. Here, we perform THz near-field imaging and spectroscopy on a model rare-earth alloy of lanthanum silicide (La-Si) which is known to exhibit diverse compositional and structural phases. We identify subwavelength spatial variations in conductivity that is manifested as alloy microstructures down to much less than 1 μm in size and is remarkably distinct from the surface topography of the material. Signal contrasts from the near-field scattering responses enable mapping the local silicon/lanthanum content differences. These observations demonstrate that THz-sSNOM offers a new avenue to investigate the compositional heterogeneity of material phases and their related nanoscale electrical as well as optical properties.
Collapse
|
3
|
Dong J, You P, Tomasino A, Yurtsever A, Morandotti R. Single-shot ultrafast terahertz photography. Nat Commun 2023; 14:1704. [PMID: 36973242 PMCID: PMC10042990 DOI: 10.1038/s41467-023-37285-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 03/07/2023] [Indexed: 03/29/2023] Open
Abstract
Multidimensional imaging of transient events has proven pivotal in unveiling many fundamental mechanisms in physics, chemistry, and biology. In particular, real-time imaging modalities with ultrahigh temporal resolutions are required for capturing ultrashort events on picosecond timescales. Despite recent approaches witnessing a dramatic boost in high-speed photography, current single-shot ultrafast imaging schemes operate only at conventional optical wavelengths, being suitable solely within an optically-transparent framework. Here, leveraging on the unique penetration capability of terahertz radiation, we demonstrate a single-shot ultrafast terahertz photography system that can capture multiple frames of a complex ultrafast scene in non-transparent media with sub-picosecond temporal resolution. By multiplexing an optical probe beam in both the time and spatial-frequency domains, we encode the terahertz-captured three-dimensional dynamics into distinct spatial-frequency regions of a superimposed optical image, which is then computationally decoded and reconstructed. Our approach opens up the investigation of non-repeatable or destructive events that occur in optically-opaque scenarios.
Collapse
Affiliation(s)
- Junliang Dong
- Institut national de la recherche scientifique, Centre Énergie Matériaux Télécommunications, Varennes, QC, J3X 1P7, Canada.
| | - Pei You
- Institut national de la recherche scientifique, Centre Énergie Matériaux Télécommunications, Varennes, QC, J3X 1P7, Canada
| | - Alessandro Tomasino
- Institut national de la recherche scientifique, Centre Énergie Matériaux Télécommunications, Varennes, QC, J3X 1P7, Canada
| | - Aycan Yurtsever
- Institut national de la recherche scientifique, Centre Énergie Matériaux Télécommunications, Varennes, QC, J3X 1P7, Canada
| | - Roberto Morandotti
- Institut national de la recherche scientifique, Centre Énergie Matériaux Télécommunications, Varennes, QC, J3X 1P7, Canada.
| |
Collapse
|
4
|
In C, Kim UJ, Choi H. Two-dimensional Dirac plasmon-polaritons in graphene, 3D topological insulator and hybrid systems. LIGHT, SCIENCE & APPLICATIONS 2022; 11:313. [PMID: 36302746 PMCID: PMC9613982 DOI: 10.1038/s41377-022-01012-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/22/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Collective oscillations of massless particles in two-dimensional (2D) Dirac materials offer an innovative route toward implementing atomically thin devices based on low-energy quasiparticle interactions. Strong confinement of near-field distribution on the 2D surface is essential to demonstrate extraordinary optoelectronic functions, providing means to shape the spectral response at the mid-infrared (IR) wavelength. Although the dynamic polarization from the linear response theory has successfully accounted for a range of experimental observations, a unified perspective was still elusive, connecting the state-of-the-art developments based on the 2D Dirac plasmon-polaritons. Here, we review recent works on graphene and three-dimensional (3D) topological insulator (TI) plasmon-polariton, where the mid-IR and terahertz (THz) radiation experiences prominent confinement into a deep-subwavelength scale in a novel optoelectronic structure. After presenting general light-matter interactions between 2D Dirac plasmon and subwavelength quasiparticle excitations, we introduce various experimental techniques to couple the plasmon-polaritons with electromagnetic radiations. Electrical and optical controls over the plasmonic excitations reveal the hybridized plasmon modes in graphene and 3D TI, demonstrating an intense near-field interaction of 2D Dirac plasmon within the highly-compressed volume. These findings can further be applied to invent optoelectronic bio-molecular sensors, atomically thin photodetectors, and laser-driven light sources.
Collapse
Affiliation(s)
- Chihun In
- Department of Physics, Freie Universität Berlin, Berlin, 14195, Germany
- Department of Physical Chemistry, Fritz-Haber-Institute of the Max-Planck-Society, Berlin, 14195, Germany
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
- Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Un Jeong Kim
- Advanced Sensor Laboratory, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do, 16419, Republic of Korea.
| | - Hyunyong Choi
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea.
- Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea.
| |
Collapse
|
5
|
Glinka YD, He T, Sun XW. Two-photon IR pumped UV-Vis transient absorption spectroscopy of Dirac fermions in the topological insulator Bi 2Se 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:465301. [PMID: 36075223 DOI: 10.1088/1361-648x/ac90a7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
It is often taken for granted that in pump-probe experiments on the topological insulator (TI) Bi2Se3using IR pumping with a commercial Ti:sapphire laser [∼800 nm (1.55 eV photon energy)], the electrons are excited in the one-photon absorption regime, even when pumped with absorbed fluences in the mJ cm-2range. Here, using UV-Vis transient absorption (TA) spectroscopy, we show that even at low-power Infrared (IR) pumping with absorbed fluences in theμJ cm-2range, the TA spectra of the TI Bi2Se3extend across a part of the UV and the entire visible region. This observation suggests unambiguously that the two-photon pumping regime accompanies the usual one-photon pumping regime even at low laser powers applied. We attribute the high efficiency of two-photon pumping to the giant nonlinearity of Dirac fermions in the Dirac surface states (SS). On the contrary, one-photon pumping is associated with the excitation of bound valence electrons in the bulk into the conduction band. Two mechanisms of absorption bleaching were also revealed since they manifest themselves in different spectral regions of probing and cause the appearance of three different relaxation dynamics. These two mechanisms were attributed to the filling of the phase-space in the Dirac SS and bulk states, followed by the corresponding Pauli blocking.
Collapse
Affiliation(s)
- Yuri D Glinka
- Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting, Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- Institute of Physics, National Academy of Sciences of Ukraine, Kyiv 03028, Ukraine
| | - Tingchao He
- College of Physics and Energy, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Xiao Wei Sun
- Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting, Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- Shenzhen Planck Innovation Technologies Pte Ltd, Longgang, Shenzhen 518112, People's Republic of China
| |
Collapse
|
6
|
Nilforoushan N, Apretna T, Song C, Boulier T, Tignon J, Dhillon S, Hanna M, Mangeney J. Ultra-broadband THz pulses with electric field amplitude exceeding 100 kV/cm at a 200 kHz repetition rate. OPTICS EXPRESS 2022; 30:15556-15565. [PMID: 35473272 DOI: 10.1364/oe.453105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
We demonstrate a table-top source delivering ultra-broadband THz pulses with electric field strength exceeding 100 kV/cm at a repetition rate of 200 kHz. The source is based on optical rectification of 23 fs pulses at 1030 nm delivered by a ytterbium-doped fiber laser followed by a nonlinear temporal compression stage. We generate THz pulses with a conversion efficiency of up to 0.11 % with a spectrum extending to 11 THz using a 1 mm thick GaP crystal and a conversion efficiency of 0.016 % with a spectrum extending to 30 THz using a 30 µm thick GaSe crystal. The essential features of the emitted THz pulse spectra are well captured by simulations of the optical rectification process relying on coupled nonlinear equations. Our ultrafast laser-based source uniquely satisfies an important requirement of nonlinear THz experiments, namely the emission of ultra-broadband THz pulses with high electric field amplitudes at high repetition rates, opening a route towards nonlinear time-resolved THz experiments with high signal-to-noise ratios.
Collapse
|
7
|
Ma Q, Grushin AG, Burch KS. Topology and geometry under the nonlinear electromagnetic spotlight. NATURE MATERIALS 2021; 20:1601-1614. [PMID: 34127824 DOI: 10.1038/s41563-021-00992-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
For many materials, a precise knowledge of their dispersion spectra is insufficient to predict their ordered phases and physical responses. Instead, these materials are classified by the geometrical and topological properties of their wavefunctions. A key challenge is to identify and implement experiments that probe or control these quantum properties. In this Review, we describe recent progress in this direction, focusing on nonlinear electromagnetic responses that arise directly from quantum geometry and topology. We give an overview of the field by discussing theoretical ideas, experiments and the materials that drive them. We conclude by discussing how these techniques can be combined with device architectures to uncover, probe and ultimately control quantum phases with emergent topological and correlated properties.
Collapse
Affiliation(s)
- Qiong Ma
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Adolfo G Grushin
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Kenneth S Burch
- Department of Physics, Boston College, Chestnut Hill, MA, USA.
| |
Collapse
|
8
|
Abstract
2D layered materials with diverse exciting properties have recently attracted tremendous interest in the scientific community. Layered topological insulator Bi2Se3 comes into the spotlight as an exotic state of quantum matter with insulating bulk states and metallic Dirac-like surface states. Its unique crystal and electronic structure offer attractive features such as broadband optical absorption, thickness-dependent surface bandgap and polarization-sensitive photoresponse, which enable 2D Bi2Se3 to be a promising candidate for optoelectronic applications. Herein, we present a comprehensive summary on the recent advances of 2D Bi2Se3 materials. The structure and inherent properties of Bi2Se3 are firstly described and its preparation approaches (i.e., solution synthesis and van der Waals epitaxy growth) are then introduced. Moreover, the optoelectronic applications of 2D Bi2Se3 materials in visible-infrared detection, terahertz detection, and opto-spintronic device are discussed in detail. Finally, the challenges and prospects in this field are expounded on the basis of current development.
Collapse
Affiliation(s)
- Fakun K. Wang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Sijie J. Yang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Tianyou Y. Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| |
Collapse
|
9
|
Kim S, Kim Y, Kim J, Choi S, Yun K, Kim D, Lim SY, Kim S, Chun SH, Park J, Eom I, Kim KS, Koo TY, Ou Y, Katmis F, Wen H, DiChiara A, Walko DA, Landahl EC, Cheong H, Sim E, Moodera J, Kim H. Ultrafast Carrier-Lattice Interactions and Interlayer Modulations of Bi 2Se 3 by X-ray Free-Electron Laser Diffraction. NANO LETTERS 2021; 21:8554-8562. [PMID: 34623164 DOI: 10.1021/acs.nanolett.1c01424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
As a 3D topological insulator, bismuth selenide (Bi2Se3) has potential applications for electrically and optically controllable magnetic and optoelectronic devices. Understanding the coupling with its topological phase requires studying the interactions of carriers with the lattice on time scales down to the subpicosecond regime. Here, we investigate the ultrafast carrier-induced lattice contractions and interlayer modulations in Bi2Se3 thin films by time-resolved diffraction using an X-ray free-electron laser. The lattice contraction depends on the carrier concentration and is followed by an interlayer expansion accompanied by oscillations. Using density functional theory and the Lifshitz model, the initial contraction can be explained by van der Waals force modulation of the confined free carrier layers. Our theoretical calculations suggest that the band inversion, related to a topological phase transition, is modulated by the expansion of the interlayer distance. These results provide insights into the topological phase control by light-induced structural change on ultrafast time scales.
Collapse
Affiliation(s)
- Sungwon Kim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Youngsam Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Jaeseung Kim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Sungwook Choi
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Kyuseok Yun
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Dongjin Kim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Soo Yeon Lim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Sunam Kim
- Pohang Accelerator Laboratory, Pohang 37673, Korea
| | | | - Jaeku Park
- Pohang Accelerator Laboratory, Pohang 37673, Korea
| | - Intae Eom
- Pohang Accelerator Laboratory, Pohang 37673, Korea
| | | | | | - Yunbo Ou
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ferhat Katmis
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Haidan Wen
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Anthony DiChiara
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Donald A Walko
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Eric C Landahl
- Department of Physics, DePaul University, Chicago, Illinois 60614, United States
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Eunji Sim
- Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Jagadeesh Moodera
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hyunjung Kim
- Department of Physics, Sogang University, Seoul 04107, Korea
| |
Collapse
|
10
|
Park H, Jeong K, Maeng I, Sim KI, Pathak S, Kim J, Hong SB, Jung TS, Kang C, Kim JH, Hong J, Cho MH. Enhanced Spin-to-Charge Conversion Efficiency in Ultrathin Bi 2Se 3 Observed by Spintronic Terahertz Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2021; 13:23153-23160. [PMID: 33945256 DOI: 10.1021/acsami.1c03168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Owing to their remarkable spin-charge conversion (SCC) efficiency, topological insulators (TIs) are the most attractive candidates for spin-orbit torque generators. The simple method of enhancing SCC efficiency is to reduce the thickness of TI films to minimize the trivial bulk contribution. However, when the thickness reaches the ultrathin regime, the SCC efficiency decreases owing to intersurface hybridization. To overcome these contrary effects, we induced dehybridization of the ultrathin TI film by breaking the inversion symmetry between surfaces. For the TI film grown on an oxygen-deficient transition-metal oxide, the unbonded transition-metal d-orbitals affected only the bottom surface, resulting in asymmetric surface band structures. Spintronic terahertz emission spectroscopy, an emerging tool for investigating the SCC characteristics, revealed that the resulting SCC efficiency in symmetry-broken ultrathin Bi2Se3 was enhanced by up to ∼2.4 times.
Collapse
Affiliation(s)
- Hanbum Park
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Kwangsik Jeong
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea
| | - InHee Maeng
- YUHS-KRIBB, Medical Convergence Research Institute, College of Medicine, Yonsei University, Seoul 03722, Republic of Korea
| | - Kyung Ik Sim
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Sachin Pathak
- Department of Physics, School of Engineering, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand, India
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jonghoon Kim
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Seok-Bo Hong
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Taek Sun Jung
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Chul Kang
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Jae Hoon Kim
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Jongill Hong
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Mann-Ho Cho
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| |
Collapse
|
11
|
Man MKL, Madéo J, Sahoo C, Xie K, Campbell M, Pareek V, Karmakar A, Wong EL, Al-Mahboob A, Chan NS, Bacon DR, Zhu X, Abdelrasoul MMM, Li X, Heinz TF, da Jornada FH, Cao T, Dani KM. Experimental measurement of the intrinsic excitonic wave function. SCIENCE ADVANCES 2021; 7:7/17/eabg0192. [PMID: 33883143 PMCID: PMC8059923 DOI: 10.1126/sciadv.abg0192] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/04/2021] [Indexed: 05/10/2023]
Abstract
An exciton, a two-body composite quasiparticle formed of an electron and hole, is a fundamental optical excitation in condensed matter systems. Since its discovery nearly a century ago, a measurement of the excitonic wave function has remained beyond experimental reach. Here, we directly image the excitonic wave function in reciprocal space by measuring the momentum distribution of electrons photoemitted from excitons in monolayer tungsten diselenide. By transforming to real space, we obtain a visual of the distribution of the electron around the hole in an exciton. Further, by also resolving the energy coordinate, we confirm the elusive theoretical prediction that the photoemitted electron exhibits an inverted energy-momentum dispersion relationship reflecting the valence band where the partner hole remains, rather than that of conduction band states of the electron.
Collapse
Affiliation(s)
- Michael K L Man
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Julien Madéo
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Chakradhar Sahoo
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
- School of Physics, University of Hyderabad, Gachibowli, Hyderabad, 500046 Telangana, India
| | - Kaichen Xie
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Marshall Campbell
- Physics Department, Center for Complex Quantum System, The University of Texas at Austin, Austin, TX 78712, USA
| | - Vivek Pareek
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Arka Karmakar
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - E Laine Wong
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Abdullah Al-Mahboob
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Nicholas S Chan
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - David R Bacon
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Xing Zhu
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Mohamed M M Abdelrasoul
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495
| | - Xiaoqin Li
- Physics Department, Center for Complex Quantum System, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tony F Heinz
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA 94720, USA
| | - Felipe H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Keshav M Dani
- Femtosecond Spectroscopy Unit, Okinawa Instittute of Science and Technology Graduate University, Onna, Okinawa, Japan 904 0495.
| |
Collapse
|
12
|
Luo L, Cheng D, Song B, Wang LL, Vaswani C, Lozano PM, Gu G, Huang C, Kim RHJ, Liu Z, Park JM, Yao Y, Ho K, Perakis IE, Li Q, Wang J. A light-induced phononic symmetry switch and giant dissipationless topological photocurrent in ZrTe 5. NATURE MATERIALS 2021; 20:329-334. [PMID: 33462464 DOI: 10.1038/s41563-020-00882-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Dissipationless currents from topologically protected states are promising for disorder-tolerant electronics and quantum computation. Here, we photogenerate giant anisotropic terahertz nonlinear currents with vanishing scattering, driven by laser-induced coherent phonons of broken inversion symmetry in a centrosymmetric Dirac material ZrTe5. Our work suggests that this phononic terahertz symmetry switching leads to formation of Weyl points, whose chirality manifests in a transverse, helicity-dependent current, orthogonal to the dynamical inversion symmetry breaking axis, via circular photogalvanic effect. The temperature-dependent topological photocurrent exhibits several distinct features: Berry curvature dominance, particle-hole reversal near conical points and chirality protection that is responsible for an exceptional ballistic transport length of ~10 μm. These results, together with first-principles modelling, indicate two pairs of Weyl points dynamically created by B1u phonons of broken inversion symmetry. Such phononic terahertz control breaks ground for coherent manipulation of Weyl nodes and robust quantum transport without application of static electric or magnetic fields.
Collapse
Affiliation(s)
- Liang Luo
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Di Cheng
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Boqun Song
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Lin-Lin Wang
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Chirag Vaswani
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - P M Lozano
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - G Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Chuankun Huang
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Richard H J Kim
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Zhaoyu Liu
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Joong-Mok Park
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Yongxin Yao
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Kaiming Ho
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA
| | - Ilias E Perakis
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Qiang Li
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA.
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
| | - Jigang Wang
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory, US Department of Energy, Ames, IA, USA.
| |
Collapse
|
13
|
Chen J, Zhang Z, Luo L, Lu Y, Song C, Cheng D, Chen X, Li W, Ren Z, Wang J, Tian H, Zhang Z, Han G. Reversible magnetism transition at ferroelectric oxide heterointerface. Sci Bull (Beijing) 2020; 65:2094-2099. [PMID: 36732962 DOI: 10.1016/j.scib.2020.09.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/11/2020] [Accepted: 09/01/2020] [Indexed: 02/04/2023]
Abstract
Oxide heterointerface is a platform to create unprecedented two-dimensional electron gas, superconductivity and ferromagnetism, arising from a polar discontinuity at the interface. In particular, the ability to tune these intriguing effects paves a way to elucidate their fundamental physics and to develop novel electronic/magnetic devices. In this work, we report for the first time that a ferroelectric polarization screening at SrTiO3/PbTiO3 interface is able to drive an electronic construction of Ti atom, giving rise to room-temperature ferromagnetism. Surprisingly, such ferromagnetism can be switched to antiferromagnetism by applying a magnetic field, which is reversible. A coupling of itinerant electrons with local moments at interfacial Ti 3d orbital was proposed to explain the magnetism. The localization of the itinerant electrons under a magnetic field is responsible for the suppression of magnetism. These findings provide new insights into interfacial magnetism and their control by magnetic field relevant interfacial electrons promising for device applications.
Collapse
Affiliation(s)
- Jialu Chen
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China
| | - Zijun Zhang
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liang Luo
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory-USDOE, Ames, IA 50011, USA
| | - Yunhao Lu
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Cheng Song
- Key Laboratory of Advanced Materials (Ministry of Education), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Di Cheng
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory-USDOE, Ames, IA 50011, USA
| | - Xing Chen
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wei Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China
| | - Zhaohui Ren
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China.
| | - Jigang Wang
- Department of Physics and Astronomy, Iowa State University and Ames Laboratory-USDOE, Ames, IA 50011, USA.
| | - He Tian
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Ze Zhang
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China; Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Gaorong Han
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University, Hangzhou 310027, China.
| |
Collapse
|
14
|
Vaswani C, Mootz M, Sundahl C, Mudiyanselage DH, Kang JH, Yang X, Cheng D, Huang C, Kim RHJ, Liu Z, Luo L, Perakis IE, Eom CB, Wang J. Terahertz Second-Harmonic Generation from Lightwave Acceleration of Symmetry-Breaking Nonlinear Supercurrents. PHYSICAL REVIEW LETTERS 2020; 124:207003. [PMID: 32501057 DOI: 10.1103/physrevlett.124.207003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/29/2020] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
We report terahertz (THz) light-induced second harmonic generation, in superconductors with inversion symmetry that forbid even-order nonlinearities. The THz second harmonic emission vanishes above the superconductor critical temperature and arises from precession of twisted Anderson pseudospins at a multicycle, THz driving frequency that is not allowed by equilibrium symmetry. We explain the microscopic physics by a dynamical symmetry breaking principle at sub-THz-cycle by using quantum kinetic modeling of the interplay between strong THz-lightwave nonlinearity and pulse propagation. The resulting nonzero integrated pulse area inside the superconductor leads to light-induced nonlinear supercurrents due to subcycle Cooper pair acceleration, in contrast to dc-biased superconductors, which can be controlled by the band structure and THz driving field below the superconducting gap.
Collapse
Affiliation(s)
- C Vaswani
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - M Mootz
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294-1170, USA
| | - C Sundahl
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D H Mudiyanselage
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - J H Kang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - X Yang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - D Cheng
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - C Huang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - R H J Kim
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Z Liu
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - L Luo
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - I E Perakis
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294-1170, USA
| | - C B Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J Wang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
15
|
Liu Z, Vaswani C, Yang X, Zhao X, Yao Y, Song Z, Cheng D, Shi Y, Luo L, Mudiyanselage DH, Huang C, Park JM, Kim RHJ, Zhao J, Yan Y, Ho KM, Wang J. Ultrafast Control of Excitonic Rashba Fine Structure by Phonon Coherence in the Metal Halide Perovskite CH_{3}NH_{3}PbI_{3}. PHYSICAL REVIEW LETTERS 2020; 124:157401. [PMID: 32357060 DOI: 10.1103/physrevlett.124.157401] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/17/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
We discover hidden Rashba fine structure in CH_{3}NH_{3}PbI_{3} and demonstrate its quantum control by vibrational coherence through symmetry-selective vibronic (electron-phonon) coupling. Above a critical threshold of a single-cycle terahertz pump field, a Raman phonon mode distinctly modulates the middle excitonic states with persistent coherence for more than ten times longer than the ones on two sides that predominately couple to infrared phonons. These vibronic quantum beats, together with first-principles modeling of phonon periodically modulated Rashba parameters, identify a threefold excitonic fine structure splitting, i.e., optically forbidden, degenerate dark states in between two bright ones with a narrow, ∼3 nm splitting. Harnessing of vibronic quantum coherence and symmetry inspires light-perovskite quantum control and sub-THz-cycle "Rashba engineering" of spin-split bands for ultimate multifunction device.
Collapse
Affiliation(s)
- Z Liu
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - C Vaswani
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - X Yang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - X Zhao
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Y Yao
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Z Song
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, USA
| | - D Cheng
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Y Shi
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - L Luo
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - D-H Mudiyanselage
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - C Huang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - J-M Park
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - R H J Kim
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - J Zhao
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Y Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, USA
| | - K-M Ho
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - J Wang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
16
|
Dartiailh MC, Hartinger S, Gourmelon A, Bendias K, Bartolomei H, Kamata H, Berroir JM, Fève G, Plaçais B, Lunczer L, Schlereth R, Buhmann H, Molenkamp LW, Bocquillon E. Dynamical Separation of Bulk and Edge Transport in HgTe-Based 2D Topological Insulators. PHYSICAL REVIEW LETTERS 2020; 124:076802. [PMID: 32142329 DOI: 10.1103/physrevlett.124.076802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
Topological effects in edge states are clearly visible on short lengths only, thus largely impeding their studies. On larger distances, one may be able to dynamically enhance topological signatures by exploiting the high mobility of edge states with respect to bulk carriers. Our work on microwave spectroscopy highlights the response of the edges which host very mobile carriers, while bulk carriers are drastically slowed down in the gap. Though the edges are denser than expected, we establish that charge relaxation occurs on short timescales and suggest that edge states can be addressed selectively on timescales over which bulk carriers are frozen.
Collapse
Affiliation(s)
- Matthieu C Dartiailh
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Simon Hartinger
- Physikalisches Institut (EP3), Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
| | - Alexandre Gourmelon
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Kalle Bendias
- Physikalisches Institut (EP3), Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
| | - Hugo Bartolomei
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Hiroshi Kamata
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Jean-Marc Berroir
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Gwendal Fève
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Bernard Plaçais
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Lukas Lunczer
- Physikalisches Institut (EP3), Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
| | - Raimund Schlereth
- Physikalisches Institut (EP3), Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
| | - Hartmut Buhmann
- Physikalisches Institut (EP3), Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
| | - Laurens W Molenkamp
- Physikalisches Institut (EP3), Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, Universität Würzburg, D-97074 Würzburg, Germany
| | - Erwann Bocquillon
- Laboratoire de Physique de l'École Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France
| |
Collapse
|
17
|
Xing X, Zhao L, Zhang W, Wang Z, Su H, Chen H, Ma G, Dai J, Zhang W. Influence of a substrate on ultrafast interfacial charge transfer and dynamical interlayer excitons in monolayer WSe 2/graphene heterostructures. NANOSCALE 2020; 12:2498-2506. [PMID: 31930248 DOI: 10.1039/c9nr09309e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Efficient interfacial light-electric interconversion in van der Waals heterostructures is critical for their optoelectronic applications. Using time-resolved terahertz spectroscopy and transient absorption spectroscopy, the charge transfer and the dynamical interlayer excitons were investigated in the heterostructures comprising monolayer WSe2 and monolayer graphene with varying stacking order on a sapphire substrate. Herein, a more comprehensive understanding of ultrafast charge transfer and exciton dynamics in two-dimensional heterostructures is shown. Owing to the effective electric field induced by the sapphire substrate, the WSe2/graphene heterostructure exhibits positive terahertz photoconductivity after photoexcitation, while negative terahertz photoconductivity is observed in the graphene/WSe2 heterostructure. The transient absorption spectra indicate that the exciton lifetimes also exhibit a considerable difference, where WSe2/graphene exhibits the longest exciton lifetime, followed by monolayer WSe2, while graphene/WSe2 exhibits the shortest lifetime. These observations provide a new idea for using van der Waals heterostructures in electronic and photonic devices.
Collapse
Affiliation(s)
- Xiao Xing
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
| | - Litao Zhao
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
| | - Wenjie Zhang
- Department of Physics, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
| | - Zhuo Wang
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
| | - Huimin Su
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
| | - Huaying Chen
- School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen, Shenzhen 518055, China
| | - Guohong Ma
- Department of Physics, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
| | - Junfeng Dai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
| | - Wenjing Zhang
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
| |
Collapse
|
18
|
Cheng D, Liu Z, Luo L, Vaswani C, Park JM, Yao Y, Song Z, Huang C, Mudiyanselage DH, Kim RHJ, Yan Y, Ho KM, Wang J. Helicity-dependent terahertz photocurrent and phonon dynamics in hybrid metal halide perovskites. J Chem Phys 2019; 151:244706. [DOI: 10.1063/1.5127767] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D. Cheng
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Z. Liu
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - L. Luo
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - C. Vaswani
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - J.-M. Park
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Y. Yao
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Z. Song
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - C. Huang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - D.-H. Mudiyanselage
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - R. H. J. Kim
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - Y. Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - K.-M. Ho
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| | - J. Wang
- Department of Physics and Astronomy and Ames Laboratory-U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
| |
Collapse
|
19
|
Miyamoto K, Sano K, Miyakawa T, Niinomi H, Toyoda K, Vallés A, Omatsu T. Generation of high-quality terahertz OAM mode based on soft-aperture difference frequency generation. OPTICS EXPRESS 2019; 27:31840-31849. [PMID: 31684408 DOI: 10.1364/oe.27.031840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate the generation of high-quality tunable terahertz (THz) vortices in an eigenmode by employing soft-aperture difference frequency generation of vortex and Gaussian modes. The generated THz vortex output exhibits a high-quality orbital angular momentum (OAM) mode with a topological charge of ℓTHz = ±1 in a frequency range of 2-6 THz. The maximum average power of the THz vortex output obtained was ∼3.3 µW at 4 THz.
Collapse
|
20
|
Wang YM, Yu JL, Zeng XL, Chen YH, Liu Y, Cheng SY, Lai YF, Yin CM, He K, Xue QK. Temperature and excitation wavelength dependence of circular and linear photogalvanic effect in a three dimensional topological insulator Bi 2Se 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:415702. [PMID: 31220819 DOI: 10.1088/1361-648x/ab2b55] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The circular (CPGE) and linear photogalvanic effect (LPGE) of a three-dimensional topological insulator Bi2Se3 thin film of seven quintuple layers excited by near-infrared (1064 nm) and mid-infrared (10.6 [Formula: see text]m) radiations have been investigated. The comparison of the CPGE current measured parallel and perpendicular to the incident plane, together with the comparison of the CPGE current under front and back illuminations, indicates that the CPGE under front illumination of 1064 nm light is dominated by the top surface states of the Bi2Se3 thin film. The CPGE current excited by 10.6 [Formula: see text]m light is about one order larger than that excited by 1064 nm light, which may be attributed to the smaller cancelation effect of the CPGE generated in the two-dimensional electron gas when excited by 10.6 [Formula: see text]m light. Under the excitation of 1064 nm light, the LPGE current is dominated by the component which shows an even parity of incident angles, while the LPGE current excited by 10.6 [Formula: see text]m light is mainly contributed by the component which is an odd parity of incident angles. Both of the CPGE and LPGE currents excited by 1064 nm decrease with increasing temperature, which may be owing to the decrease of the momentum relaxation time and the stronger electron-electron scattering with increasing temperature, respectively.
Collapse
Affiliation(s)
- Y M Wang
- Institute of Micro/Nano Devices and Solar Cells, School of Physics and Information Engineering, Fuzhou University, Fuzhou, People's Republic of China
| | | | | | | | | | | | | | | | | | | |
Collapse
|