1
|
Wang Y, Dou W. Electron Transfer at Molecule-Metal Interfaces under Floquet Engineering: Rate Constant and Floquet Marcus Theory. ACS PHYSICAL CHEMISTRY AU 2024; 4:160-166. [PMID: 38560755 PMCID: PMC10979498 DOI: 10.1021/acsphyschemau.3c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/05/2023] [Accepted: 12/05/2023] [Indexed: 04/04/2024]
Abstract
Electron transfer (ET) at molecule-metal or molecule-semiconductor interfaces is a fundamental reaction that underlies all electrochemical processes and substrate-mediated surface photochemistry. In this study, we show that ET rates near a metal surface can be significantly manipulated by periodic driving (e.g., Floquet engineering). We employ the Floquet surface hopping and Floquet electronic friction algorithms developed previously to calculate the ET rates near the metal surface as a function of driving amplitudes and driving frequencies. We find that ET rates have a turnover effect when the driving frequencies increase. A Floquet Marcus theory is further formulated to analyze such a turnover effect. We then benchmark the Floquet Marcus theory against Floquet surface hopping and Floquet electronic friction methods, indicating that the Floquet Marcus theory works in the strong nonadiabatic regimes but fails in the weak nonadiabatic regimes. We hope these theoretical tools will be useful to study ET rates in the plasmonic cavity and plasmon-assisted photocatalysis.
Collapse
Affiliation(s)
- Yu Wang
- Department
of Chemistry, School of Science, Westlake
University, Hangzhou, Zhejiang 310024, China
- Institute
of Natural Sciences, Westlake Institute
for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Wenjie Dou
- Department
of Chemistry, School of Science, Westlake
University, Hangzhou, Zhejiang 310024, China
- Institute
of Natural Sciences, Westlake Institute
for Advanced Study, Hangzhou, Zhejiang 310024, China
| |
Collapse
|
2
|
Ginsberg JS, Jadidi MM, Zhang J, Chen CY, Tancogne-Dejean N, Chae SH, Patwardhan GN, Xian L, Watanabe K, Taniguchi T, Hone J, Rubio A, Gaeta AL. Phonon-enhanced nonlinearities in hexagonal boron nitride. Nat Commun 2023; 14:7685. [PMID: 38001087 PMCID: PMC10673846 DOI: 10.1038/s41467-023-43501-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
Polar crystals can be driven into collective oscillations by optical fields tuned to precise resonance frequencies. As the amplitude of the excited phonon modes increases, novel processes scaling non-linearly with the applied fields begin to contribute to the dynamics of the atomic system. Here we show two such optical nonlinearities that are induced and enhanced by the strong phonon resonance in the van der Waals crystal hexagonal boron nitride (hBN). We predict and observe large sub-picosecond duration signals due to four-wave mixing (FWM) during resonant excitation. The resulting FWM signal allows for time-resolved observation of the crystal motion. In addition, we observe enhancements of third-harmonic generation with resonant pumping at the hBN transverse optical phonon. Phonon-induced nonlinear enhancements are also predicted to yield large increases in high-harmonic efficiencies beyond the third.
Collapse
Affiliation(s)
- Jared S Ginsberg
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, NY, 10027, USA.
| | - M Mehdi Jadidi
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, NY, 10027, USA
| | - Jin Zhang
- Max Planck Institute for Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg, 22761, Germany.
| | - Cecilia Y Chen
- Department of Electrical Engineering, Columbia University, New York, New York, NY, 10027, USA
| | - Nicolas Tancogne-Dejean
- Max Planck Institute for Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg, 22761, Germany
| | - Sang Hoon Chae
- Department of Mechanical Engineering, Columbia University, New York, New York, NY, 10027, USA
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Gauri N Patwardhan
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, NY, 10027, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Lede Xian
- Max Planck Institute for Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg, 22761, Germany
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - James Hone
- Department of Mechanical Engineering, Columbia University, New York, New York, NY, 10027, USA
| | - Angel Rubio
- Max Planck Institute for Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg, 22761, Germany.
- Center for Computational Quantum Physics, Simons Foundation Flatiron Institute, New York, NY, 10010, USA.
| | - Alexander L Gaeta
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, NY, 10027, USA.
- Department of Electrical Engineering, Columbia University, New York, New York, NY, 10027, USA.
| |
Collapse
|
3
|
Wang C, Liu X, Chen Q, Chen D, Wang Y, Meng S. Coherent-Phonon-Driven Intervalley Scattering and Rabi Oscillation in Multivalley 2D Materials. PHYSICAL REVIEW LETTERS 2023; 131:066401. [PMID: 37625067 DOI: 10.1103/physrevlett.131.066401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 05/15/2023] [Accepted: 06/29/2023] [Indexed: 08/27/2023]
Abstract
Resolving the complete electron scattering dynamics mediated by coherent phonons is crucial for understanding electron-phonon couplings beyond equilibrium. Here we present a time-resolved theoretical investigation on strongly coupled ultrafast electron and phonon dynamics in monolayer WSe_{2}, with a focus on the intervalley scattering from the optically "bright" K state to "dark" Q state. We find that the strong coherent lattice vibration along the longitudinal acoustic phonon mode [LA(M)] can drastically promote K-to-Q transition on a timescale of ∼400 fs, comparable with previous experimental observation on thermal-phonon-mediated electron dynamics. Further, this coherent-phonon-driven intervalley scattering occurs in an unconventional steplike manner and further induces an electronic Rabi oscillation. By constructing a two-level model and quantitatively comparing with ab initio dynamic simulations, we uncover the critical role of nonadiabatic coupling effects. Finally, a new strategy is proposed to effectively tune the intervalley scattering rates by varying the coherent phonon amplitude, which could be realized via light-induced nonlinear phononics that we hope will spark experimental investigation.
Collapse
Affiliation(s)
- Chenyu Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xinbao Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Daqiang Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yaxian Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| |
Collapse
|
4
|
Esin I, Esterlis I, Demler E, Refael G. Generating Coherent Phonon Waves in Narrow-Band Materials: A Twisted Bilayer Graphene Phaser. PHYSICAL REVIEW LETTERS 2023; 130:147001. [PMID: 37084441 DOI: 10.1103/physrevlett.130.147001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/17/2023] [Indexed: 05/03/2023]
Abstract
Twisted bilayer graphene (TBG) exhibits extremely low Fermi velocities for electrons, with the speed of sound surpassing the Fermi velocity. This regime enables the use of TBG for amplifying vibrational waves of the lattice through stimulated emission, following the same principles of operation of free-electron lasers. Our Letter proposes a lasing mechanism relying on the slow-electron bands to produce a coherent beam of acoustic phonons. We propose a device based on undulated electrons in TBG, which we dub the phaser. The device generates phonon beams in a terahertz (THz) frequency range, which can then be used to produce THz electromagnetic radiation. The ability to generate coherent phonons in solids breaks new ground in controlling quantum memories, probing quantum states, realizing nonequilibrium phases of matter, and designing new types of THz optical devices.
Collapse
Affiliation(s)
- Iliya Esin
- Department of Physics and Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - Ilya Esterlis
- Department of Physics, Harvard University, Cambridge Massachusetts 02138, USA
| | - Eugene Demler
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Gil Refael
- Department of Physics and Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| |
Collapse
|
5
|
Controlling Floquet states on ultrashort time scales. Nat Commun 2022; 13:7103. [DOI: 10.1038/s41467-022-34973-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/14/2022] [Indexed: 11/21/2022] Open
Abstract
AbstractThe advent of ultrafast laser science offers the unique opportunity to combine Floquet engineering with extreme time resolution, further pushing the optical control of matter into the petahertz domain. However, what is the shortest driving pulse for which Floquet states can be realised remains an unsolved matter, thus limiting the application of Floquet theory to pulses composed by many optical cycles. Here we ionized Ne atoms with few-femtosecond pulses of selected time duration and show that a Floquet state can be observed already with a driving field that lasts for only 10 cycles. For shorter pulses, down to 2 cycles, the finite lifetime of the driven state can still be explained using an analytical model based on Floquet theory. By demonstrating that the amplitude and number of Floquet-like sidebands in the photoelectron spectrum can be controlled not only with the driving laser pulse intensity and frequency, but also by its duration, our results add a new lever to the toolbox of Floquet engineering.
Collapse
|
6
|
Probing phonon dynamics with multidimensional high harmonic carrier-envelope-phase spectroscopy. Proc Natl Acad Sci U S A 2022; 119:e2204219119. [PMID: 35704757 PMCID: PMC9231615 DOI: 10.1073/pnas.2204219119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High harmonic generation (HHG) has recently been established as a powerful method for probing ultrafast electron dynamics in solids. However, it remains unknown if HHG can be similarly applied for probing lattice distortions such as phonons. Specifically, it is unclear if the extreme nonlinearity of HHG can contribute to enhanced temporal resolution or sensitivity for probing lattice dynamics (compared to other, perturbative, methods). Here, we theoretically explore HHG in solids with active phonons. We present a pump-probe and multidimensional spectroscopy approach that relies on carrier-envelope-phase-sensitivity, in which HHG is highly sensitive for phonon dynamics. Strikingly, the predicted temporal resolution is ∼1 femtosecond, much below the probe pulse duration, owing to the subcycle nature of the approach. We explore pump-probe high harmonic generation (HHG) from monolayer hexagonal-boron-nitride, where a terahertz pump excites coherent optical phonons that are subsequently probed by an intense infrared pulse that drives HHG. We find, through state-of-the-art ab initio calculations, that the structure of the emission spectrum is attenuated by the presence of coherent phonons and no longer comprises discrete harmonic orders, but rather a continuous emission in the plateau region. The HHG yield strongly oscillates as a function of the pump-probe delay, corresponding to ultrafast changes in the lattice such as specific bond compression or stretching dynamics. We further show that in the regime where the excited phonon period and the pulse duration are of the same order of magnitude, the HHG process becomes sensitive to the carrier-envelope phase (CEP) of the driving field, even though the pulse duration is so long that no such sensitivity is observed in the absence of coherent phonons. The degree of CEP sensitivity versus pump-probe delay is shown to be a highly selective measure for instantaneous structural changes in the lattice, providing an approach for ultrafast multidimensional HHG spectroscopy. Remarkably, the obtained temporal resolution for phonon dynamics is ∼1 femtosecond, which is much shorter than the probe pulse duration because of the inherent subcycle contrast mechanism. Our work paves the way toward routes of probing phonons and ultrafast material structural changes with subcycle temporal resolution and provides a mechanism for controlling the HHG spectrum.
Collapse
|
7
|
Tzur ME, Neufeld O, Bordo E, Fleischer A, Cohen O. Selection rules in symmetry-broken systems by symmetries in synthetic dimensions. Nat Commun 2022; 13:1312. [PMID: 35288566 PMCID: PMC8921280 DOI: 10.1038/s41467-022-29080-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 02/17/2022] [Indexed: 11/22/2022] Open
Abstract
Selection rules are often considered a hallmark of symmetry. Here, we employ symmetry-breaking degrees of freedom as synthetic dimensions to demonstrate that symmetry-broken systems systematically exhibit a specific class of symmetries and selection rules. These selection rules constrain the scaling of a system’s observables (non-perturbatively) as it transitions from symmetric to symmetry-broken. Specifically, we drive bi-elliptical high harmonic generation (HHG), and observe that the scaling of the HHG spectrum with the pump’s ellipticities is constrained by selection rules corresponding to symmetries in synthetic dimensions. We then show the generality of this phenomenon by analyzing periodically-driven (Floquet) systems subject to two driving fields, tabulating the resulting synthetic symmetries for (2 + 1)D Floquet groups, and deriving the corresponding selection rules for high harmonic generation (HHG) and other phenomena. The presented class of symmetries and selection rules opens routes for ultrafast spectroscopy of phonon-polarization, spin-orbit coupling, symmetry-protected dark bands, and more. The authors introduce the concept of real-synthetic symmetries and use it as a tool to derive selection rules in seemingly symmetry-broken strong-field interactions. These symmetries and their corresponding selection rules can be applied in various systems form harmonic generation to topological photonics
Collapse
|
8
|
Medina Dueñas J, Calvo HL, Foa Torres LEF. Copropagating Edge States Produced by the Interaction between Electrons and Chiral Phonons in Two-Dimensional Materials. PHYSICAL REVIEW LETTERS 2022; 128:066801. [PMID: 35213173 DOI: 10.1103/physrevlett.128.066801] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/12/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Unlike the chirality of electrons, the intrinsic chirality of phonons has only surfaced in recent years. Here, we report on the effects of the interaction between electrons and chiral phonons in two-dimensional materials by using a nonperturbative solution. We show that chiral phonons introduce inelastic Umklapp processes resulting in copropagating edge states that coexist with a continuum. Transport simulations further reveal the robustness of the edge states. Our results hint on the possibility of having a metal embedded with hybrid electron-phonon states of matter.
Collapse
Affiliation(s)
- Joaquín Medina Dueñas
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, 837.0415 Santiago, Chile
| | - Hernán L Calvo
- Instituto de Física Enrique Gaviola (CONICET) and FaMAF, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
| | - Luis E F Foa Torres
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, 837.0415 Santiago, Chile
| |
Collapse
|
9
|
Durden AS, Levine BG. Floquet Time-Dependent Configuration Interaction for Modeling Ultrafast Electron Dynamics. J Chem Theory Comput 2022; 18:795-806. [DOI: 10.1021/acs.jctc.1c01009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Andrew S. Durden
- Department of Chemistry and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, United States
| | - Benjamin G. Levine
- Department of Chemistry and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, United States
| |
Collapse
|
10
|
Ergeçen E, Ilyas B, Mao D, Po HC, Yilmaz MB, Kim J, Park JG, Senthil T, Gedik N. Magnetically brightened dark electron-phonon bound states in a van der Waals antiferromagnet. Nat Commun 2022; 13:98. [PMID: 35013277 PMCID: PMC8748959 DOI: 10.1038/s41467-021-27741-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 12/08/2021] [Indexed: 11/27/2022] Open
Abstract
In van der Waals (vdW) materials, strong coupling between different degrees of freedom can hybridize elementary excitations into bound states with mixed character1–3. Correctly identifying the nature and composition of these bound states is key to understanding their ground state properties and excitation spectra4,5. Here, we use ultrafast spectroscopy to reveal bound states of d-orbitals and phonons in 2D vdW antiferromagnet NiPS3. These bound states manifest themselves through equally spaced phonon replicas in frequency domain. These states are optically dark above the Néel temperature and become accessible with magnetic order. By launching this phonon and spectrally tracking its amplitude, we establish the electronic origin of bound states as localized d–d excitations. Our data directly yield electron-phonon coupling strength which exceeds the highest known value in 2D systems6. These results demonstrate NiPS3 as a platform to study strong interactions between spins, orbitals and lattice, and open pathways to coherent control of 2D magnets. Van der Waals materials can exhibit strong coupling between the lattice and other degrees of freedom. Here, Ergeçen et al reveal the presence of bound states emerging from the strong interaction between the lattice vibrations and d-orbitals in the van der Waals antiferromagnet NiPS3.
Collapse
Affiliation(s)
- Emre Ergeçen
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Batyr Ilyas
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Dan Mao
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Hoi Chun Po
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.,Department of Physics, Hong Kong Univesity of Science and Technology, Clear Water Bay, Hong Kong, 999077, China
| | - Mehmet Burak Yilmaz
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Junghyun Kim
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea.,Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Je-Geun Park
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea.,Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - T Senthil
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA.
| |
Collapse
|
11
|
Neufeld O, Tancogne-Dejean N, De Giovannini U, Hübener H, Rubio A. Light-Driven Extremely Nonlinear Bulk Photogalvanic Currents. PHYSICAL REVIEW LETTERS 2021; 127:126601. [PMID: 34597089 DOI: 10.1103/physrevlett.127.126601] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
We predict the generation of bulk photocurrents in materials driven by bichromatic fields that are circularly polarized and corotating. The nonlinear photocurrents have a fully controllable directionality and amplitude without requiring carrier-envelope-phase stabilization or few-cycle pulses, and can be generated with photon energies much smaller than the band gap (reducing heating in the photoconversion process). We demonstrate with ab initio calculations that the photocurrent generation mechanism is universal and arises in gaped materials (Si, diamond, MgO, hBN), in semimetals (graphene), and in two- and three-dimensional systems. Photocurrents are shown to rely on sub-laser-cycle asymmetries in the nonlinear response that build-up coherently from cycle to cycle as the conduction band is populated. Importantly, the photocurrents are always transverse to the major axis of the co-circular lasers regardless of the material's structure and orientation (analogously to a Hall current), which we find originates from a generalized time-reversal symmetry in the driven system. At high laser powers (∼10^{13} W/cm^{2}) this symmetry can be spontaneously broken by vast electronic excitations, which is accompanied by an onset of carrier-envelope-phase sensitivity and ultrafast many-body effects. Our results are directly applicable for efficient light-driven control of electronics, and for enhancing sub-band-gap bulk photogalvanic effects.
Collapse
Affiliation(s)
- Ofer Neufeld
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg 22761, Germany
| | - Nicolas Tancogne-Dejean
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg 22761, Germany
| | - Umberto De Giovannini
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg 22761, Germany
- IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao, Spain
- Nano-Bio Spectroscopy Group, Universidad del País Vasco UPV/EHU, 20018 San Sebastián, Spain
| | - Hannes Hübener
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg 22761, Germany
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Hamburg 22761, Germany
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, New York, New York 10010, USA
- Nano-Bio Spectroscopy Group, Universidad del País Vasco UPV/EHU, 20018 San Sebastián, Spain
| |
Collapse
|
12
|
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.
Collapse
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
| | | |
Collapse
|
13
|
Reitz M, Genes C. Floquet engineering of molecular dynamics via infrared coupling. J Chem Phys 2020; 153:234305. [PMID: 33353327 DOI: 10.1063/5.0033382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We discuss Floquet engineering of dissipative molecular systems through periodic driving of an infrared-active vibrational transition, either directly or via a cavity mode. Following a polaron quantum Langevin equation approach, we derive correlation functions and stationary quantities showing strongly modified optical response of the infrared-dressed molecule. The coherent excitation of molecular vibrational modes in combination with the modulation of electronic degrees of freedom due to vibronic coupling can lead to both enhanced vibronic coherence and control over vibrational sideband amplitudes. The additional coupling to an infrared cavity allows for the controlled suppression of undesired sidebands, an effect stemming from the Purcell enhancement of vibrational relaxation rates.
Collapse
Affiliation(s)
- Michael Reitz
- Max Planck Institute for the Science of Light, Staudtstraße 2, D-91058 Erlangen, Germany
| | - Claudiu Genes
- Max Planck Institute for the Science of Light, Staudtstraße 2, D-91058 Erlangen, Germany
| |
Collapse
|
14
|
Wang K, He J, Zhang M, Wang H, Zhang G. Magnon-phonon interaction in antiferromagnetic two-dimensional MXenes. NANOTECHNOLOGY 2020; 31:435705. [PMID: 32650317 DOI: 10.1088/1361-6528/aba4cf] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Antiferromagnetic material possesses excellent robustness to an external magnetic field perturbation, which makes it promising in application of spintronic devices. The magnon-phonon interaction plays a vital role in spintronic devices. In this work, we performed first-principles calculation to study the effect of magnon-phonon interaction on magnon spectra of the antiferromagnetic MXenes Cr2TiC2FCl, and calculated the phonon dominated magnon relaxation time based on the magnon spectra broadening. Due to the large exchange constants across Cr-Cr pairs, high magnon energy is found in Cr2TiC2FCl. We find that compared with the acoustic magnons, the optical magnons have stronger interaction with phonon modes. Moreover, relaxation time of optical magnons and acoustic magnons have quite different wavevector dependence. Our results about spin coupling to specific phonon polarizations can shed light on the understanding of magnon damping and energy dissipation in two-dimensional antiferromagnetic materials.
Collapse
Affiliation(s)
- Ke Wang
- Xidian University, Xi'an, Shanxi Province 710071, People's Republic of China
| | | | | | | | | |
Collapse
|
15
|
De Giovannini U, Hübener H, Sato SA, Rubio A. Direct Measurement of Electron-Phonon Coupling with Time-Resolved ARPES. PHYSICAL REVIEW LETTERS 2020; 125:136401. [PMID: 33034494 DOI: 10.1103/physrevlett.125.136401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
Time- and angular- resolved photoelectron spectroscopy is a powerful technique to measure electron dynamics in solids. Recent advances in this technique have facilitated band and energy resolved observations of the effect that excited phonons, have on the electronic structure. Here, we show with the help of ab initio simulations that the Fourier analysis of the time-resolved measurements of solids with excited phonon modes enables the determination of the band- and mode-resolved electron-phonon coupling directly from the experimental data without any additional input from theory. Such an observation is not restricted to regions of strong electron-phonon coupling and does not require strongly excited or hot phonons, but can be employed to monitor the dynamical renormalization of phonons in driven phases of matter.
Collapse
Affiliation(s)
- Umberto De Giovannini
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - Hannes Hübener
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - Shunsuke A Sato
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free Electron Laser Science, 22761 Hamburg, Germany
- Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free Electron Laser Science, 22761 Hamburg, Germany
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth avenue, New York, New York 10010, USA
| |
Collapse
|
16
|
Observation of the polaronic character of excitons in a two-dimensional semiconducting magnet CrI 3. Nat Commun 2020; 11:4780. [PMID: 32963250 PMCID: PMC7508859 DOI: 10.1038/s41467-020-18627-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/27/2020] [Indexed: 11/16/2022] Open
Abstract
Exciton dynamics can be strongly affected by lattice vibrations through electron-phonon coupling. This is rarely explored in two-dimensional magnetic semiconductors. Focusing on bilayer CrI3, we first show the presence of strong electron-phonon coupling through temperature-dependent photoluminescence and absorption spectroscopy. We then report the observation of periodic broad modes up to the 8th order in Raman spectra, attributed to the polaronic character of excitons. We establish that this polaronic character is dominated by the coupling between the charge-transfer exciton at 1.96 eV and a longitudinal optical phonon at 120.6 cm−1. We further show that the emergence of long-range magnetic order enhances the electron-phonon coupling strength by ~50% and that the transition from layered antiferromagnetic to ferromagnetic order tunes the spectral intensity of the periodic broad modes, suggesting a strong coupling among the lattice, charge and spin in two-dimensional CrI3. Our study opens opportunities for tailoring light-matter interactions in two-dimensional magnetic semiconductors. Exciton dynamics can be strongly affected by lattice vibrations through electron-phonon (e-ph) coupling. Here, the authors show the presence of strong e-ph coupling in bilayer CrI3 and observe a Raman feature with periodic broad modes up to the 8th order, attributed to the polaronic character of excitons.
Collapse
|
17
|
Perfetto E, Stefanucci G. Floquet Topological Phase of Nondriven p-Wave Nonequilibrium Excitonic Insulators. PHYSICAL REVIEW LETTERS 2020; 125:106401. [PMID: 32955296 DOI: 10.1103/physrevlett.125.106401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
The nontrivial topology of p-wave superfluids makes these systems attractive candidates in information technology. In this work we report on the topological state of a p-wave nonequilibrium excitonic insulator (NEQ-EI) and show how to steer a nontopological band insulator with bright p excitons toward this state by a suitable laser pulse, thus achieving a dynamical topological phase transition. The underlying mechanism behind the transition is the broken gauge-symmetry of the NEQ-EI which causes self-sustained persistent oscillations of the excitonic condensate and hence a Floquet topological state for high enough exciton densities. We show the formation of Floquet Majorana modes at the boundaries of the open system and discuss unique topological spectral signatures for time-resolved ARPES experiments. We emphasize that the topological properties of a p-wave NEQ-EI arise exclusively from the electron-hole Coulomb interaction as the system is not driven by external fields.
Collapse
Affiliation(s)
- E Perfetto
- Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - G Stefanucci
- Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| |
Collapse
|
18
|
Tancogne-Dejean N, Oliveira MJT, Andrade X, Appel H, Borca CH, Le Breton G, Buchholz F, Castro A, Corni S, Correa AA, De Giovannini U, Delgado A, Eich FG, Flick J, Gil G, Gomez A, Helbig N, Hübener H, Jestädt R, Jornet-Somoza J, Larsen AH, Lebedeva IV, Lüders M, Marques MAL, Ohlmann ST, Pipolo S, Rampp M, Rozzi CA, Strubbe DA, Sato SA, Schäfer C, Theophilou I, Welden A, Rubio A. Octopus, a computational framework for exploring light-driven phenomena and quantum dynamics in extended and finite systems. J Chem Phys 2020; 152:124119. [PMID: 32241132 DOI: 10.1063/1.5142502] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Over the last few years, extraordinary advances in experimental and theoretical tools have allowed us to monitor and control matter at short time and atomic scales with a high degree of precision. An appealing and challenging route toward engineering materials with tailored properties is to find ways to design or selectively manipulate materials, especially at the quantum level. To this end, having a state-of-the-art ab initio computer simulation tool that enables a reliable and accurate simulation of light-induced changes in the physical and chemical properties of complex systems is of utmost importance. The first principles real-space-based Octopus project was born with that idea in mind, i.e., to provide a unique framework that allows us to describe non-equilibrium phenomena in molecular complexes, low dimensional materials, and extended systems by accounting for electronic, ionic, and photon quantum mechanical effects within a generalized time-dependent density functional theory. This article aims to present the new features that have been implemented over the last few years, including technical developments related to performance and massive parallelism. We also describe the major theoretical developments to address ultrafast light-driven processes, such as the new theoretical framework of quantum electrodynamics density-functional formalism for the description of novel light-matter hybrid states. Those advances, and others being released soon as part of the Octopus package, will allow the scientific community to simulate and characterize spatial and time-resolved spectroscopies, ultrafast phenomena in molecules and materials, and new emergent states of matter (quantum electrodynamical-materials).
Collapse
Affiliation(s)
- Nicolas Tancogne-Dejean
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Micael J T Oliveira
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Xavier Andrade
- Quantum Simulations Group, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - Heiko Appel
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Carlos H Borca
- Quantum Simulations Group, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - Guillaume Le Breton
- Département de Physique, École Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon Cedex 07, France
| | - Florian Buchholz
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Alberto Castro
- Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Calle Mariano Esquillor, 50018 Zaragoza, Spain
| | - Stefano Corni
- Dipartimento di Scienze Chimiche, Università degli studi di Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Alfredo A Correa
- Quantum Simulations Group, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - Umberto De Giovannini
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Alain Delgado
- Xanadu, 777 Bay Street, Toronto, Ontario M5G 2C8, Canada
| | - Florian G Eich
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Johannes Flick
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Gabriel Gil
- Dipartimento di Scienze Chimiche, Università degli studi di Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Adrián Gomez
- Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Calle Mariano Esquillor, 50018 Zaragoza, Spain
| | - Nicole Helbig
- Nanomat/Qmat/CESAM and ETSF, Université de Liège, B-4000 Sart-Tilman, Belgium
| | - Hannes Hübener
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - René Jestädt
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Joaquim Jornet-Somoza
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Ask H Larsen
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco, 20018 San Sebastián, Spain
| | - Irina V Lebedeva
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco, 20018 San Sebastián, Spain
| | - Martin Lüders
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Miguel A L Marques
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Sebastian T Ohlmann
- Max Planck Computing and Data Facility, Gießenbachstraße 2, 85741 Garching, Germany
| | - Silvio Pipolo
- Université de Lille, CNRS, Centrale Lille, ENSCL, Université d' Artois UMR 8181-UCCS Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Markus Rampp
- Max Planck Computing and Data Facility, Gießenbachstraße 2, 85741 Garching, Germany
| | - Carlo A Rozzi
- CNR - Istituto Nanoscienze, via Campi 213a, 41125 Modena, Italy
| | - David A Strubbe
- Department of Physics, School of Natural Sciences, University of California, Merced, California 95343, USA
| | - Shunsuke A Sato
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Christian Schäfer
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Iris Theophilou
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Alicia Welden
- Quantum Simulations Group, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
| |
Collapse
|
19
|
Schüler M, De Giovannini U, Hübener H, Rubio A, Sentef MA, Werner P. Local Berry curvature signatures in dichroic angle-resolved photoelectron spectroscopy from two-dimensional materials. SCIENCE ADVANCES 2020; 6:eaay2730. [PMID: 32158939 PMCID: PMC7048418 DOI: 10.1126/sciadv.aay2730] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 12/04/2019] [Indexed: 06/07/2023]
Abstract
Topologically nontrivial two-dimensional materials hold great promise for next-generation optoelectronic applications. However, measuring the Hall or spin-Hall response is often a challenge and practically limited to the ground state. An experimental technique for tracing the topological character in a differential fashion would provide useful insights. In this work, we show that circular dichroism angle-resolved photoelectron spectroscopy provides a powerful tool that can resolve the topological and quantum-geometrical character in momentum space. In particular, we investigate how to map out the signatures of the momentum-resolved Berry curvature in two-dimensional materials by exploiting its intimate connection to the orbital polarization. A spin-resolved detection of the photoelectrons allows one to extend the approach to spin-Chern insulators. The present proposal can be extended to address topological properties in materials out of equilibrium in a time-resolved fashion.
Collapse
Affiliation(s)
- Michael Schüler
- Stanford Institute for Materials and Energy Sciences (SIMES), SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Umberto De Giovannini
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Hannes Hübener
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue, New York, NY 10010, USA
| | - Michael A. Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| |
Collapse
|
20
|
Lü XL, Xie H. Topological phases and pumps in the Su-Schrieffer-Heeger model periodically modulated in time. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:495401. [PMID: 31434065 DOI: 10.1088/1361-648x/ab3d72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
By the Floquet theory, we transform the Su-Schrieffer-Heeger model with the periodically modulated nearest-neighbor (NN) and next-nearest-neighbor (NNN) interactions into an effective 2D model, which holds the total Chern number of ±1 modulated by the parameter θ. Under a staggered electric potential, the topological phase diagrams of the effective 2D model are reshaped and similar to the well-known Haldane model. While under a staggered Zeeman field, the topological phase diagram has the same shape as the former case, but with different Chern numbers, such as the spin and valley Chern numbers. With the combination of the staggered Zeeman field and the electric field, the effective 2D model holds even richer topological phases. At last, we find some types of topological pump, which can generate the time-averaged current without any bias voltage. The current depends on their different Chern numbers. In other words, we can modulate the parameters to obtain various Chern numbers to control the topological pump.
Collapse
Affiliation(s)
- Xiao-Long Lü
- Department of Physics, Chongqing University, Chongqing, People's Republic of China
| | | |
Collapse
|
21
|
Peng Y, Refael G. Floquet Second-Order Topological Insulators from Nonsymmorphic Space-Time Symmetries. PHYSICAL REVIEW LETTERS 2019; 123:016806. [PMID: 31386389 DOI: 10.1103/physrevlett.123.016806] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 06/10/2023]
Abstract
We propose a systematic way of constructing Floquet second-order topological insulators (SOTIs) based on time-glide symmetry, a nonsymmorphic space-time symmetry that is unique in Floquet systems. In particular, we are able to show that the static enlarged Hamiltonian in the frequency domain acquires reflection symmetry, which is inherited from the time-glide symmetry of the original system. As a consequence, one can construct a variety of time-glide symmetric Floquet SOTIs using the knowledge of static SOTIs. Moreover, the time-glide symmetry only needs to be implemented approximately in practice, enhancing the prospects of experimental realizations. We consider two examples, a 2D system in class AIII and a 3D system in class A, to illustrate our ideas, and then present a general recipe for constructing Floquet SOTIs in all symmetry classes.
Collapse
Affiliation(s)
- Yang Peng
- Institute of Quantum Information and Matter and Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Walter Burke Institute for Theoretical Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - Gil Refael
- Institute of Quantum Information and Matter and Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
| |
Collapse
|
22
|
Ciccarino CJ, Christensen T, Sundararaman R, Narang P. Dynamics and Spin-Valley Locking Effects in Monolayer Transition Metal Dichalcogenides. NANO LETTERS 2018; 18:5709-5715. [PMID: 30067036 DOI: 10.1021/acs.nanolett.8b02300] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Transition metal dichalcogenides have been the primary materials of interest in the field of valleytronics for their potential in information storage, yet the limiting factor has been achieving long valley decoherence times. We explore the dynamics of four monolayer TMDCs (MoS2, MoSe2, WS2, WSe2) using ab initio calculations to describe electron-electron and electron-phonon interactions. By comparing calculations which both omit and include relativistic effects, we isolate the impact of spin-resolved spin-orbit coupling on transport properties. In our work, we find that spin-orbit coupling increases carrier lifetimes at the valence band edge by an order of magnitude due to spin-valley locking, with a proportional increase in the hole mobility at room temperature. At temperatures of 50 K, we find intervalley scattering times on the order of 100 ps, with a maximum value of ∼140 ps in WSe2. Finally, we calculate excited-carrier generation profiles which indicate that direct transitions dominate across optical energies, even for WSe2 which has an indirect band gap. Our results highlight the intriguing interplay between spin and valley degrees of freedom critical for valleytronic applications. Further, our work points toward interesting quantum properties on-demand in transition metal dichalcogenides that could be leveraged via driving spin, valley, and phonon degrees of freedom.
Collapse
Affiliation(s)
- Christopher J Ciccarino
- John A. Paulson School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts , United States
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts , United States
| | - Thomas Christensen
- Department of Physics , Massachusetts Institute of Technology , Cambridge , Massachusetts , United States
| | - Ravishankar Sundararaman
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , Troy , New York , United States
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts , United States
| |
Collapse
|
23
|
Bolmatov D, Soloviov D, Zav'yalov D, Sharpnack L, Agra-Kooijman DM, Kumar S, Zhang J, Liu M, Katsaras J. Anomalous Nanoscale Optoacoustic Phonon Mixing in Nematic Mesogens. J Phys Chem Lett 2018; 9:2546-2553. [PMID: 29706065 DOI: 10.1021/acs.jpclett.8b00926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent inelastic X-ray scattering (IXS) experiments on mesogens have revealed entirely new capabilities with regards to their nanoscale phonon-assisted heat management. Mesogens such as nematic liquid crystals (LCs) are appealing systems for study because their structure and morphology can easily be tuned. We report on Q-resolved ultra-high-resolution IXS, X-ray diffraction, and THz time-domain spectroscopy experiments combined with large-scale all-atom molecular dynamics simulations on the dynamic properties of 5CB LCs. For the first time, we observe a strong mixing of phonon excitations originating from independent in-phase and out-of-phase van-der-Waals-mediated displacement patterns. The coexistence of transverse acoustic and optical modes of 5CB LCs at near room temperature is revealed through the emergent transverse phonon gap and THz light-phonon coupling taking place within the same energy range. Furthermore, our experimental observations are supported by analysis showing correlations of spontaneous fluctuations of LCs on picosecond time scales. These findings are significant for the design of a new generation of soft molecular vibration-sensitive nanoacoustic and optomechanical applications.
Collapse
Affiliation(s)
- Dima Bolmatov
- Neutron Scattering Directorate , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
- Department of Physics and Astronomy , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Dmytro Soloviov
- Frank Laboratory of Neutron Physics , Joint Institute for Nuclear Research , Dubna 141980 , Russia
- Taras Shevchenko National University of Kyiv , Kyiv 01033 , Ukraine
- Moscow Institute of Physics and Technology , Dolgoprudny 141701 , Russia
| | - Dmitry Zav'yalov
- Volgograd State Technical University , Volgograd 400005 , Russia
| | - Lewis Sharpnack
- European Synchrotron Radiation Facility , Grenoble 38043 , France
| | - Deña M Agra-Kooijman
- Liquid Crystal Institute , Kent State University , Kent , Ohio 44242 , United States
| | - Satyendra Kumar
- Division of Research and Department of Physics , University at Albany , Albany , New York 12222 , United States
| | - Jiawei Zhang
- Department of Physics and Astronomy , Stony Brook University , Stony Brook , New York 11794 , United States
| | - Mengkun Liu
- Department of Physics and Astronomy , Stony Brook University , Stony Brook , New York 11794 , United States
| | - John Katsaras
- Neutron Scattering Directorate , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
- Department of Physics and Astronomy , University of Tennessee , Knoxville , Tennessee 37996 , United States
| |
Collapse
|
24
|
Shin D, Hübener H, De Giovannini U, Jin H, Rubio A, Park N. Phonon-driven spin-Floquet magneto-valleytronics in MoS 2. Nat Commun 2018; 9:638. [PMID: 29434265 PMCID: PMC5809408 DOI: 10.1038/s41467-018-02918-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/09/2018] [Indexed: 11/21/2022] Open
Abstract
Two-dimensional materials equipped with strong spin–orbit coupling can display novel electronic, spintronic, and topological properties originating from the breaking of time or inversion symmetry. A lot of interest has focused on the valley degrees of freedom that can be used to encode binary information. By performing ab initio time-dependent density functional simulation on MoS2, here we show that the spin is not only locked to the valley momenta but strongly coupled to the optical E″ phonon that lifts the lattice mirror symmetry. Once the phonon is pumped so as to break time-reversal symmetry, the resulting Floquet spectra of the phonon-dressed spins carry a net out-of-plane magnetization (≈0.024μB for single-phonon quantum) even though the original system is non-magnetic. This dichroic magnetic response of the valley states is general for all 2H semiconducting transition-metal dichalcogenides and can be probed and controlled by infrared coherent laser excitation. In 2H semiconducting transition-metal dichalcogenides the valley-selective excitation has been achieved with circularly polarized photons. Here, the authors show that circularly polarized phonons produce a valley-dependent dynamic spin state as a result of strong spin-phonon coupling.
Collapse
Affiliation(s)
- Dongbin Shin
- Department of Physics, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan, 44919, Korea
| | - Hannes Hübener
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Luruper Chaussee 149, Hamburg, 22761, Germany
| | - Umberto De Giovannini
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Luruper Chaussee 149, Hamburg, 22761, Germany
| | - Hosub Jin
- Department of Physics, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan, 44919, Korea
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Luruper Chaussee 149, Hamburg, 22761, Germany. .,Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue New York, New York, NY, 10010, USA. .,Nano-Bio Spectroscopy Group, Departamento de Fisica de Materiales, Universidad del País Vasco UPV/EHU, San Sebastián, 20018, Spain.
| | - Noejung Park
- Department of Physics, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan, 44919, Korea. .,Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Luruper Chaussee 149, Hamburg, 22761, Germany.
| |
Collapse
|