1
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Hu SQ, Chen DQ, Du LL, Meng S. Solid-state high harmonic spectroscopy for all-optical band structure probing of high-pressure quantum states. Proc Natl Acad Sci U S A 2024; 121:e2316775121. [PMID: 38300874 PMCID: PMC10861900 DOI: 10.1073/pnas.2316775121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 12/11/2023] [Indexed: 02/03/2024] Open
Abstract
High pressure has triggered various novel states/properties in condensed matter, as the most representative and dramatic example being near-room-temperature superconductivity in highly pressured hydrides (~200 GPa). However, the mechanism of superconductivity is not confirmed, due to the lacking of effective approach to probe the electronic band structure under such high pressures. Here, we theoretically propose that the band structure and electron-phonon coupling (EPC) of high-pressure quantum states can be probed by solid-state high harmonic generation (sHHG). This strategy is investigated in high-pressure Im-3m H3S by the state-of-the-art first-principles time-dependent density-functional theory simulations, where the sHHG is revealed to be strongly dependent on the electronic structures and EPC. The dispersion of multiple bands near the Fermi level is effectively retrieved along different momentum directions. Our study provides unique insights into the potential all-optical route for band structure and EPC probing of high-pressure quantum states, which is expected to be helpful for the experimental exploration of high-pressure superconductivity in the future.
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Affiliation(s)
- Shi-Qi Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, People’s Republic of China
| | - Da-Qiang Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, People’s Republic of China
| | - Lan-Lin Du
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, People’s Republic of China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, People’s Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People’s Republic of China
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2
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Zheng Z, Shi Y, Zhou JJ, Prezhdo OV, Zheng Q, Zhao J. Ab initio real-time quantum dynamics of charge carriers in momentum space. NATURE COMPUTATIONAL SCIENCE 2023; 3:532-541. [PMID: 38177418 DOI: 10.1038/s43588-023-00456-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 04/21/2023] [Indexed: 01/06/2024]
Abstract
Application of the non-adiabatic molecular dynamics (NAMD) approach is limited to studying carrier dynamics in the momentum space, as a supercell is required to sample the phonon excitation and electron-phonon (e-ph) interaction at different momenta in a molecular dynamics simulation. Here we develop an ab initio approach for the real-time charge carrier quantum dynamics in the momentum space (NAMD_k) by directly introducing e-ph coupling into the Hamiltonian based on the harmonic approximation. The NAMD_k approach maintains the zero-point energy and includes memory effects of carrier dynamics. The application of NAMD_k to the hot carrier dynamics in graphene reveals the phonon-specific relaxation mechanism. An energy threshold of 0.2 eV-defined by two optical phonon modes-separates the hot electron relaxation into fast and slow regions with lifetimes of pico- and nanoseconds, respectively. The NAMD_k approach provides an effective tool to understand real-time carrier dynamics in the momentum space for different materials.
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Affiliation(s)
- Zhenfa Zheng
- Department of Physics, ICQD/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Yongliang Shi
- Department of Physics, ICQD/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
- Center for Spintonics and Quantum Systerms, State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, China.
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
| | - Jin-Jian Zhou
- School of Physics, Beijing Institute of Technology, Beijing, China
| | - Oleg V Prezhdo
- Departments of Chemistry, Physics, and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Qijing Zheng
- Department of Physics, ICQD/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
| | - Jin Zhao
- Department of Physics, ICQD/Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China.
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3
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Song C, Yang Q, Liu X, Zhao H, Zhang C, Meng S. Electronic Origin of Laser-Induced Ferroelectricity in SrTiO 3. J Phys Chem Lett 2023; 14:576-583. [PMID: 36633437 DOI: 10.1021/acs.jpclett.2c03078] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Although ultrafast control of the nonthermally driven ferroelectric transition of paraelectric SrTiO3 was achieved under laser excitation, the underlying mechanism and dynamics of the photoinduced phase transition remain ambiguous. Here, the determinant formation mechanism of ultrafast ferroelectricity in SrTiO3 is traced by nonadiabatic dynamics simulations. That is, the selective excitation of multiple phonons, induced by photoexcited electrons through the strong correlation between electronic excitation and lattice distortion, results in the breaking of the crystal central symmetry and the onset of ferroelectricity. The accompanying population transition between 3dz2 and 3dx2-y2 orbitals excites multiple phonon branches, including the two high-energy longitudinal optical modes, so as to drive the titanium ion away from the center of the oxygen octahedron and generate a metastable ferroelectric phase. Our findings reveal a cooperative electronic and ionic driving mechanism for the laser-induced ferroelectricity that provides new schemes for the optical control of ultrafast quantum states.
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Affiliation(s)
- Chenchen Song
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Qing Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Xinbao Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Hui Zhao
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Cui Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
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4
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Classical Nuclear Motion: Comparison to Approaches with Quantum Mechanical Nuclear Motion. HYDROGEN 2022. [DOI: 10.3390/hydrogen4010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ab initio molecular dynamics combines a classical description of nuclear motion with a density-functional description of the electronic cloud. This approach nicely describes chemical reactions. A possible conclusion is that a quantum mechanical description of nuclear motion is not needed. Using Occam’s razor, this means that, being the simpler approach, classical nuclear motion is preferable. In this paper, it is claimed that nuclear motion is classical, and this hypothesis will be tested in comparison to methods with quantum mechanical nuclear motion. In particular, we apply ab initio molecular dynamics to two photoreactions involving hydrogen. Hydrogen, as the lightest element, is often assumed to show quantum mechanical tunneling. We will see that the classical picture is fully sufficient. The quantum mechanical view leads to phenomena that are difficult to understand, such as the entanglement of nuclear motion. In contrast, it is easy to understand the simple classical picture which assumes that nuclear motion is steady and uniform unless a force is acting. Of course, such a hypothesis must be verified for many systems and phenomena, and this paper is one more step in this direction.
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5
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He F, Ren X, Jiang J, Zhang G, He L. Real-Time, Time-Dependent Density Functional Theory Study on Photoinduced Isomerizations of Azobenzene Under a Light Field. J Phys Chem Lett 2022; 13:427-432. [PMID: 34989580 DOI: 10.1021/acs.jpclett.1c03442] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The trans to cis photoisomerization of azobenzene and its reverse (i.e., the cis to trans) processes are studied using real-time propagation time-dependent density functional theory combined with molecular dynamics for ions. We show that the wavelength of the applied laser may significantly affect the transition process. The simulations also show that the photon-excited electrons play essential roles in the isomerization processes, in which the hot electrons couple to phonon modes that drive the transitions.
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Affiliation(s)
- Fuxiang He
- Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xinguo Ren
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jun Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guozhen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lixin He
- Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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6
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Lloyd-Hughes J, Oppeneer PM, Pereira Dos Santos T, Schleife A, Meng S, Sentef MA, Ruggenthaler M, Rubio A, Radu I, Murnane M, Shi X, Kapteyn H, Stadtmüller B, Dani KM, da Jornada FH, Prinz E, Aeschlimann M, Milot RL, Burdanova M, Boland J, Cocker T, Hegmann F. The 2021 ultrafast spectroscopic probes of condensed matter roadmap. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:353001. [PMID: 33951618 DOI: 10.1088/1361-648x/abfe21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
In the 60 years since the invention of the laser, the scientific community has developed numerous fields of research based on these bright, coherent light sources, including the areas of imaging, spectroscopy, materials processing and communications. Ultrafast spectroscopy and imaging techniques are at the forefront of research into the light-matter interaction at the shortest times accessible to experiments, ranging from a few attoseconds to nanoseconds. Light pulses provide a crucial probe of the dynamical motion of charges, spins, and atoms on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Furthermore, strong light pulses can drive materials into unusual phases, with exotic properties. In this roadmap we describe the current state-of-the-art in experimental and theoretical studies of condensed matter using ultrafast probes. In each contribution, the authors also use their extensive knowledge to highlight challenges and predict future trends.
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Affiliation(s)
- J Lloyd-Hughes
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, PO Box 516, S-75120 Uppsala, Sweden
| | - T Pereira Dos Santos
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - A Schleife
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - S Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - M Ruggenthaler
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - A Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco UPV/EHU 20018 San Sebastián, Spain
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, United States of America
| | - I Radu
- Department of Physics, Freie Universität Berlin, Germany
- Max Born Institute, Berlin, Germany
| | - M Murnane
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - X Shi
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - H Kapteyn
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - B Stadtmüller
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - K M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
| | - F H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, 94305, CA, United States of America
| | - E Prinz
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - M Aeschlimann
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - R L Milot
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - M Burdanova
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - J Boland
- Photon Science Institute, Department of Electrical and Electronic Engineering, University of Manchester, United Kingdom
| | - T Cocker
- Michigan State University, United States of America
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7
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Pandeya P, Aikens CM. Real-Time Electron Dynamics Study of Plasmon-Mediated Photocatalysis on an Icosahedral Al 13-1 Nanocluster. J Phys Chem A 2021; 125:4847-4860. [PMID: 34048246 DOI: 10.1021/acs.jpca.1c02924] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nitrogen bond dissociation is one of the important steps in the Haber-Bosch process, where N2 is catalytically converted to NH3; however, the dissociation of the nitrogen triple bond is difficult to achieve. In this study, we investigate the possibility of nitrogen activation using plasmonic excitation of an icosahedral aluminum nanocluster. Real-time time-dependent density functional theory is employed to study the electron dynamics of the Al13-1 and [Al13N2]-1 systems. Step and trapezoidal electric fields with field strengths of 0.001 and 0.01 au and different polarization directions are applied to the systems, and the electron dynamics are analyzed. Because the occupation of nitrogen antibonding orbitals could potentially activate the N-N bond, we investigated the single-particle electronic transitions corresponding to an excitation from an occupied (O) to virtual (V) molecular orbitals (POV) of [Al13N2]-1. We found that N2 antibonding orbitals are more likely to become populated with stronger fields and also by using off-resonance fields.
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Affiliation(s)
- Pratima Pandeya
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Christine M Aikens
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
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8
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Zhou H, He F, Chong Y, He L, Jiang J, Luo Y, Zhang G. Bridged Azobenzene Enables Dynamic Control of Through-Space Charge Transfer for Photochemical Conversion. J Phys Chem Lett 2021; 12:3868-3874. [PMID: 33856794 DOI: 10.1021/acs.jpclett.1c00772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Through-space charge transfer (TSCT) has become a thriving strategy of modulating photogenerated charges in organic photoresponsive molecular systems for potential applications in luminescence, optoelectronics, and photochemical conversion. Yet fixed configuration between electron donor (D) and acceptor (A) is disadvantageous to mitigate charge recombination undermining their performances. By carrying out first-principle simulations, we proposed a protocol enabling dynamic control of TSCT within a D-A system by use of a bridged azobenzene (BAB), whose configuration is self-adaptive upon photoexcitation. While the Z-isomer of BAB facilitates π-π stacking of D-A pair with designated frontier orbital alignment to ensure TSCT, the E-isomer of BAB breaks that stacking and restrains charge recombination. Further, as a CO2 molecule is weakly bound to the anionic acceptor, the former goes bent as a result of charge transfer from the latter, suggesting a path for photodriven CO2 reduction aided by such a donor-switch-acceptor system. Our proof-of-concept study shows the potential of using specific photoswitch to adaptively steer spatial electron transfer within stacked π systems toward photochemical conversion.
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Affiliation(s)
- Huiting Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fuxiang He
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yuanyuan Chong
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lixin He
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jun Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yi Luo
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guozhen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
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9
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Gao S, Liu L, Wen B, Zhang X. Monolayer InSe photodetector with strong anisotropy and surface-bound excitons. Phys Chem Chem Phys 2021; 23:6075-6083. [PMID: 33683275 DOI: 10.1039/d1cp00255d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The in-plane anisotropy of monolayer InSe plays a critical role in the application of photodetectors. In this work, through nonequilibrium Green's function density functional theory (NEGF-DFT) and time-dependent density functional theory (TD-DFT) calculations, we investigated the anisotropic quantum transport in darkness and under linearly polarized light, and explored the role of surface-bound excitons in the anisotropic photocurrent. The anisotropic dark quantum transport is attributed to different potential barriers in the zigzag and armchair orientations (Id-zig/Id-arm = 1.2 × 102). Linearly polarized photocurrent calculations show that the extinction ratio reaches a maximum value of 105.67. Moreover, surface-bound exciton calculations via TD-DFT revealed that the strong anisotropic photocurrent derives from surface-bound excitons generated in the In 5pz, Se 4pz, and Se 4dz2 orbitals. InSe shows tremendous potential for use in field-effect transistors, flexible nano- and optoelectronics, and polarized light devices.
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Affiliation(s)
- Siyan Gao
- Institute of Nanosurface Science and Engineering, Guangdong Provincial Key Laboratory of Micro/Nano, Shenzhen University, Shenzhen 518060, China.
| | - Liang Liu
- Institute of Nanosurface Science and Engineering, Guangdong Provincial Key Laboratory of Micro/Nano, Shenzhen University, Shenzhen 518060, China.
| | - Bo Wen
- Institute of Nanosurface Science and Engineering, Guangdong Provincial Key Laboratory of Micro/Nano, Shenzhen University, Shenzhen 518060, China.
| | - Xi Zhang
- Institute of Nanosurface Science and Engineering, Guangdong Provincial Key Laboratory of Micro/Nano, Shenzhen University, Shenzhen 518060, China.
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10
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Cheng Y, Hong H, Zhao H, Wu C, Pan Y, Liu C, Zuo Y, Zhang Z, Xie J, Wang J, Yu D, Ye Y, Meng S, Liu K. Ultrafast Optical Modulation of Harmonic Generation in Two-Dimensional Materials. NANO LETTERS 2020; 20:8053-8058. [PMID: 33112622 DOI: 10.1021/acs.nanolett.0c02972] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The modulation of optical harmonic generation in two-dimensional (2D) materials is of paramount importance in nanophotonic and nano-optoelectronic devices for their applications in optical switching and communication. However, an effective route with ultrafast modulation speed, ultrahigh modulation depth, and broad operation wavelength range is awaiting a full exploration. Here, we report that an optical pump can dynamically modulate the third harmonic generation (THG) of a graphene monolayer with a relative modulation depth above 90% at a time scale of 2.5 ps for a broad frequency ranging from near-infrared to ultraviolet. Our observation, together with the real-time, time-dependent density functional theory (TDDFT) simulations, reveals that this modulation process stems from nonlinear dynamics of the photoexcited carriers in graphene. The superior performance of the nonlinear all-optical modulator based on 2D materials paves the way for its potential applications including nanolasers and optical communication circuits.
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Affiliation(s)
- Yang Cheng
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
| | - Hao Hong
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
| | - Hui Zhao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chunchun Wu
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yu Pan
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
| | - Can Liu
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
- Physical Science Laboratory, Huairou National Comprehensive Science Center, Beijing 101400, China
| | - Yonggang Zuo
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhihong Zhang
- International Center for Quantum Materials, Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
- Physical Science Laboratory, Huairou National Comprehensive Science Center, Beijing 101400, China
| | - Jin Xie
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
| | - Jinhuan Wang
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yu Ye
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
| | - Sheng Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing 100871, China
- International Center for Quantum Materials, Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
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11
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Lakhotia H, Kim HY, Zhan M, Hu S, Meng S, Goulielmakis E. Laser picoscopy of valence electrons in solids. Nature 2020; 583:55-59. [PMID: 32612227 DOI: 10.1038/s41586-020-2429-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/01/2020] [Indexed: 11/09/2022]
Abstract
Valence electrons contribute a small fraction of the total electron density of materials, but they determine their essential chemical, electronic and optical properties. Strong laser fields can probe electrons in valence orbitals1-3 and their dynamics4-6 in the gas phase. Previous laser studies of solids have associated high-harmonic emission7-12 with the spatial arrangement of atoms in the crystal lattice13,14 and have used terahertz fields to probe interatomic potential forces15. Yet the direct, picometre-scale imaging of valence electrons in solids has remained challenging. Here we show that intense optical fields interacting with crystalline solids could enable the imaging of valence electrons at the picometre scale. An intense laser field with a strength that is comparable to the fields keeping the valence electrons bound in crystals can induce quasi-free electron motion. The harmonics of the laser field emerging from the nonlinear scattering of the valence electrons by the crystal potential contain the critical information that enables picometre-scale, real-space mapping of the valence electron structure. We used high harmonics to reconstruct images of the valence potential and electron density in crystalline magnesium fluoride and calcium fluoride with a spatial resolution of about 26 picometres. Picometre-scale imaging of valence electrons could enable direct probing of the chemical, electronic, optical and topological properties of materials.
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Affiliation(s)
- H Lakhotia
- Institut für Physik, Universität Rostock, Rostock, Germany.,Max-Planck-Institut für Quantenoptik, Garching, Germany
| | - H Y Kim
- Institut für Physik, Universität Rostock, Rostock, Germany.,Max-Planck-Institut für Quantenoptik, Garching, Germany
| | - M Zhan
- Institut für Physik, Universität Rostock, Rostock, Germany.,Max-Planck-Institut für Quantenoptik, Garching, Germany
| | - S Hu
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - S Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - E Goulielmakis
- Institut für Physik, Universität Rostock, Rostock, Germany. .,Max-Planck-Institut für Quantenoptik, Garching, Germany.
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12
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Lian C, Zhang SJ, Hu SQ, Guan MX, Meng S. Ultrafast charge ordering by self-amplified exciton-phonon dynamics in TiSe 2. Nat Commun 2020; 11:43. [PMID: 31896745 PMCID: PMC6940384 DOI: 10.1038/s41467-019-13672-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 11/14/2019] [Indexed: 11/24/2022] Open
Abstract
The origin of charge density waves (CDWs) in TiSe\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}$$\end{document}2 has long been debated, mainly due to the difficulties in identifying the timescales of the excitonic pairing and electron–phonon coupling (EPC). Without a time-resolved and microscopic mechanism, one has to assume simultaneous appearance of CDW and periodic lattice distortions (PLD). Here, we accomplish a complete separation of ultrafast exciton and PLD dynamics and unravel their interplay in our real-time time-dependent density functional theory simulations. We find that laser pulses knock off the exciton order and induce a homogeneous bonding–antibonding transition in the initial 20 fs, then the weakened electronic order triggers ionic movements antiparallel to the original PLD. The EPC comes into play after the initial 20 fs, and the two processes mutually amplify each other leading to a complete inversion of CDW ordering. The self-amplified dynamics reproduces the evolution of band structures in agreement with photoemission experiments. Hence we resolve the key processes in the initial dynamics of CDWs that help elucidate the underlying mechanism. The physical origins of charge density waves in 1T-TiSe2 and their response to ultrafast excitation have long been a topic of theoretical and experimental debate. Here the authors present an ab initio theory that successfully captures the observed dynamics of charge density wave formation.
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Affiliation(s)
- Chao Lian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Sheng-Jie Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Shi-Qi Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Meng-Xue Guan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China. .,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, P. R. China. .,Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China.
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Lian C, Ali ZA, Kwon H, Wong BM. Indirect but Efficient: Laser-Excited Electrons Can Drive Ultrafast Polarization Switching in Ferroelectric Materials. J Phys Chem Lett 2019; 10:3402-3407. [PMID: 31181930 DOI: 10.1021/acs.jpclett.9b01046] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To enhance the efficiency of next-generation ferroelectric (FE) electronic devices, new techniques for controlling ferroelectric polarization switching are required. While most prior studies have attempted to induce polarization switching via the excitation of phonons, these experimental techniques required intricate and expensive terahertz sources and have not been completely successful. Here, we propose a new mechanism for rapidly and efficiently switching the FE polarization via laser-tuning of the underlying dynamical potential energy surface. Using time-dependent density functional calculations, we observe an ultrafast switching of the FE polarization in BaTiO3 within 200 fs. A laser pulse can induce a charge density redistribution that reduces the original FE charge order. This excitation results in both desirable and highly directional ionic forces that are always opposite to the original FE displacements. Our new mechanism enables the reversible switching of the FE polarization with optical pulses that can be produced from existing 800 nm experimental laser sources.
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Affiliation(s)
- Chao Lian
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, and Department of Physics & Astronomy , University of California-Riverside , Riverside , California 92521 , United States
| | - Zulfikhar A Ali
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, and Department of Physics & Astronomy , University of California-Riverside , Riverside , California 92521 , United States
| | - Hyuna Kwon
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, and Department of Physics & Astronomy , University of California-Riverside , Riverside , California 92521 , United States
| | - Bryan M Wong
- Department of Chemical & Environmental Engineering, Materials Science & Engineering Program, and Department of Physics & Astronomy , University of California-Riverside , Riverside , California 92521 , United States
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