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Peng B, Lange GF, Bennett D, Wang K, Slager RJ, Monserrat B. Photoinduced Electronic and Spin Topological Phase Transitions in Monolayer Bismuth. PHYSICAL REVIEW LETTERS 2024; 132:116601. [PMID: 38563950 DOI: 10.1103/physrevlett.132.116601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 02/09/2024] [Indexed: 04/04/2024]
Abstract
Ultrathin bismuth exhibits rich physics including strong spin-orbit coupling, ferroelectricity, nontrivial topology, and light-induced structural dynamics. We use ab initio calculations to show that light can induce structural transitions to four transient phases in bismuth monolayers. These light-induced phases exhibit nontrivial topological character, which we illustrate using the recently introduced concept of spin bands and spin-resolved Wilson loops. Specifically, we find that the topology changes via the closing of the electron and spin band gaps during photoinduced structural phase transitions, leading to distinct edge states. Our study provides strategies to tailor electronic and spin topology via ultrafast control of photoexcited carriers and associated structural dynamics.
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Affiliation(s)
- Bo Peng
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Gunnar F Lange
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Daniel Bennett
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Kang Wang
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Robert-Jan Slager
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Bartomeu Monserrat
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
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2
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Horn-von Hoegen M. Structural dynamics at surfaces by ultrafast reflection high-energy electron diffraction. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:021301. [PMID: 38495951 PMCID: PMC10942804 DOI: 10.1063/4.0000234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/13/2024] [Indexed: 03/19/2024]
Abstract
Many fundamental processes of structural changes at surfaces occur on a pico- or femtosecond timescale. In order to study such ultrafast processes, we have combined modern surface science techniques with fs-laser pulses in a pump-probe scheme. Grazing incidence of the electrons ensures surface sensitivity in ultrafast reflection high-energy electron diffraction (URHEED). Utilizing the Debye-Waller effect, we studied the nanoscale heat transport from an ultrathin film through a hetero-interface or the damping of vibrational excitations in monolayer adsorbate systems on the lower ps-timescale. By means of spot profile analysis, the different cooling rates of epitaxial Ge nanostructures of different size and strain state were determined. The excitation and relaxation dynamics of a driven phase transition far away from thermal equilibrium is demonstrated using the In-induced (8 × 2) reconstruction on Si(111). This Peierls-distorted surface charge density wave system exhibits a discontinuous phase transition of first order at 130 K from a (8 × 2) insulating ground state to (4 × 1) metallic excited state. Upon excitation by a fs-laser pulse, this structural phase transition is non-thermally driven in only 700 fs into the excited state. A small barrier of 40 meV hinders the immediate recovery of the ground state, and the system is found in a metastable supercooled state for up to few nanoseconds.
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Affiliation(s)
- Michael Horn-von Hoegen
- Department of Physics and Center for Nanointegration CENIDE, University of Duisburg-Essen, Lotharstrasse. 1, 47057 Duisburg, Germany
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3
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Lu W, Nicoul M, Shymanovich U, Tarasevitch A, Horn-von Hoegen M, von der Linde D, Sokolowski-Tinten K. A modular table-top setup for ultrafast x-ray diffraction. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:013002. [PMID: 38190494 DOI: 10.1063/5.0181132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 12/09/2023] [Indexed: 01/10/2024]
Abstract
We present a table-top setup for femtosecond time-resolved x-ray diffraction based on a Cu Kα (8.05 keV) laser driven plasma x-ray source. Due to its modular design, it provides high accessibility to its individual components (e.g., x-ray optics and sample environment). The Kα-yield of the source is optimized using a pre-pulse scheme. A magnifying multilayer x-ray mirror with Montel-Helios geometry is used to collect the emitted radiation, resulting in a quasi-collimated flux of more than 105 Cu Kα photons/pulse impinging on the sample under investigation at a repetition rate of 10 Hz. A gas ionization chamber detector is placed right after the x-ray mirror and used for the normalization of the diffraction signals, enabling the measurement of relative signal changes of less than 1% even at the given low repetition rate. Time-resolved diffraction experiments on laser-excited epitaxial Bi films serve as an example to demonstrate the capabilities of the setup. The setup can also be used for Debye-Scherrer type measurements on poly-crystalline samples.
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4
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Krapivin V, Gu M, Hickox-Young D, Teitelbaum SW, Huang Y, de la Peña G, Zhu D, Sirica N, Lee MC, Prasankumar RP, Maznev AA, Nelson KA, Chollet M, Rondinelli JM, Reis DA, Trigo M. Ultrafast Suppression of the Ferroelectric Instability in KTaO_{3}. PHYSICAL REVIEW LETTERS 2022; 129:127601. [PMID: 36179158 DOI: 10.1103/physrevlett.129.127601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/23/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
We use an x-ray free-electron laser to study the lattice dynamics following photoexcitation with ultrafast near-UV light (wavelength 266 nm, 50 fs pulse duration) of the incipient ferroelectric potassium tantalate, KTaO_{3}. By probing the lattice dynamics corresponding to multiple Brillouin zones through the x-ray diffuse scattering with pulses from the Linac Coherent Light Source (LCLS) (wavelength 1.3 Å and <10 fs pulse duration), we observe changes in the diffuse intensity associated with a hardening of the transverse acoustic phonon branches along Γ to X and Γ to M. Using force constants from density functional theory, we fit the quasiequilibrium intensity and obtain the instantaneous lattice temperature and density of photoexcited charge carriers. The density functional theory calculations demonstrate that photoexcitation transfers charge from oxygen 2p derived π-bonding orbitals to Ta 5d derived antibonding orbitals, further suppressing the ferroelectric instability and increasing the stability of the cubic, paraelectric structure.
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Affiliation(s)
- Viktor Krapivin
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Mingqiang Gu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - D Hickox-Young
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - S W Teitelbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Y Huang
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - G de la Peña
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D Zhu
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - N Sirica
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M-C Lee
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A A Maznev
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
| | - K A Nelson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
| | - M Chollet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - James M Rondinelli
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - D A Reis
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - M Trigo
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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5
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Priyadarshi S, Gonzalez-Vallejo I, Hauf C, Reimann K, Woerner M, Elsaesser T. Phonon-Induced Relocation of Valence Charge in Boron Nitride Observed by Ultrafast X-Ray Diffraction. PHYSICAL REVIEW LETTERS 2022; 128:136402. [PMID: 35426722 DOI: 10.1103/physrevlett.128.136402] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 01/14/2022] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
The impact of coherent phonon excitations on the valence charge distribution in cubic boron nitride is mapped by femtosecond x-ray powder diffraction. Zone-edge transverse acoustic (TA) two-phonon excitations generated by an impulsive Raman process induce a steplike increase of diffracted x-ray intensity. Charge density maps derived from transient diffraction patterns reveal a spatial transfer of valence charge from the interstitial region onto boron and nitrogen atoms. This transfer is modulated with a frequency of 250 GHz due to a coherent superposition of TA phonons related to the ^{10}B and ^{11}B isotopes. Nuclear and electronic degrees of freedom couple through many-body Coulomb interactions.
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Affiliation(s)
- Shekhar Priyadarshi
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | | | - Christoph Hauf
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Klaus Reimann
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Michael Woerner
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Thomas Elsaesser
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
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6
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Abstract
Advances over the past decade have presented new avenues to achieve control over material properties using intense pulses of electromagnetic radiation, with frequencies ranging from optical (approximately 1 PHz, or 1015 Hz) down to below 1 THz (1012 Hz). Some of these new developments have arisen from new experimental methods to drive and observe transient material properties, while others have emerged from new computational techniques that have made nonequilibrium dynamics more tractable to our understanding. One common issue with most attempts to realize control using electromagnetic pulses is the dissipation of energy, which in many cases poses a limit due to uncontrolled heating and has led to strong interest in using lower frequency and/or highly specific excitations to minimize this effect. Emergent developments in experimental tools using shaped X-ray pulses may in the future offer new possibilities for material control, provided that the issue of heat dissipation can be resolved for higher frequency light. The concept of using appropriately shaped pulses of light to control the properties of materials has a range of potential applications, and relies on an understanding of intricate couplings within the material.![]()
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Affiliation(s)
- Steven L Johnson
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
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7
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Mankowsky R, Sander M, Zerdane S, Vonka J, Bartkowiak M, Deng Y, Winkler R, Giorgianni F, Matmon G, Gerber S, Beaud P, Lemke HT. New insights into correlated materials in the time domain-combining far-infrared excitation with x-ray probes at cryogenic temperatures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:374001. [PMID: 34098537 DOI: 10.1088/1361-648x/ac08b5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Abstract
Modern techniques for the investigation of correlated materials in the time domain combine selective excitation in the THz frequency range with selective probing of coupled structural, electronic and magnetic degrees of freedom using x-ray scattering techniques. Cryogenic sample temperatures are commonly required to prevent thermal occupation of the low energy modes and to access relevant material ground states. Here, we present a chamber optimized for high-field THz excitation and (resonant) x-ray diffraction at sample temperatures between 5 and 500 K. Directly connected to the beamline vacuum and featuring both a Beryllium window and an in-vacuum detector, the chamber covers the full (2-12.7) keV energy range of the femtosecond x-ray pulses available at the Bernina endstation of the SwissFEL free electron laser. Successful commissioning experiments made use of the energy tunability to selectively track the dynamics of the structural, magnetic and orbital order of Ca2RuO4and Tb2Ti2O7at the Ru (2.96 keV) and Tb (7.55 keV)L-edges, respectively. THz field amplitudes up to 1.12 MV cm-1peak field were demonstrated and used to excite the samples at temperatures as low as 5 K.
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Affiliation(s)
| | | | | | - Jakub Vonka
- Paul Scherrer Institute, Villigen, Switzerland
| | | | - Yunpei Deng
- Paul Scherrer Institute, Villigen, Switzerland
| | - Rafael Winkler
- Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | | | - Guy Matmon
- Paul Scherrer Institute, Villigen, Switzerland
| | | | - Paul Beaud
- Paul Scherrer Institute, Villigen, Switzerland
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8
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Bauerhenne B, Lipp VP, Zier T, Zijlstra ES, Garcia ME. Self-Learning Method for Construction of Analytical Interatomic Potentials to Describe Laser-Excited Materials. PHYSICAL REVIEW LETTERS 2020; 124:085501. [PMID: 32167343 DOI: 10.1103/physrevlett.124.085501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 12/19/2019] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
Large-scale simulations using interatomic potentials provide deep insight into the processes occurring in solids subject to external perturbations. The atomistic description of laser-induced ultrafast nonthermal phenomena, however, constitutes a particularly difficult case and has so far not been possible on experimentally accessible length scales and timescales because of two main reasons: (i) ab initio simulations are restricted to a very small number of atoms and ultrashort times and (ii) simulations relying on electronic temperature- (T_{e}) dependent interatomic potentials do not reach the necessary ab initio accuracy. Here we develop a self-learning method for constructing T_{e}-dependent interatomic potentials which permit ultralarge-scale atomistic simulations of systems suddenly brought to extreme nonthermal states with density-functional theory (DFT) accuracy. The method always finds the global minimum in the parameter space. We derive a highly accurate analytical T_{e}-dependent interatomic potential Φ(T_{e}) for silicon that yields a remarkably good description of laser-excited and -unexcited Si bulk and Si films. Using Φ(T_{e}) we simulate the laser excitation of Si nanoparticles and find strong damping of their breathing modes due to nonthermal melting.
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Affiliation(s)
- Bernd Bauerhenne
- Theoretical Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Vladimir P Lipp
- Theoretical Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Tobias Zier
- Theoretical Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Eeuwe S Zijlstra
- Theoretical Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Martin E Garcia
- Theoretical Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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9
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Krishnamoorthy A, Lin MF, Zhang X, Weninger C, Ma R, Britz A, Tiwary CS, Kochat V, Apte A, Yang J, Park S, Li R, Shen X, Wang X, Kalia R, Nakano A, Shimojo F, Fritz D, Bergmann U, Ajayan P, Vashishta P. Optical Control of Non-Equilibrium Phonon Dynamics. NANO LETTERS 2019; 19:4981-4989. [PMID: 31260315 DOI: 10.1021/acs.nanolett.9b01179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The light-induced selective population of short-lived far-from-equilibrium vibration modes is a promising approach for controlling ultrafast and irreversible structural changes in functional nanomaterials. However, this requires a detailed understanding of the dynamics and evolution of these phonon modes and their coupling to the excited-state electronic structure. Here, we combine femtosecond mega-electronvolt electron diffraction experiments on a prototypical layered material, MoTe2, with non-adiabatic quantum molecular dynamics simulations and ab initio electronic structure calculations to show how non-radiative energy relaxation pathways for excited electrons can be tuned by controlling the optical excitation energy. We show how the dominant intravalley and intervalley scattering mechanisms for hot and band-edge electrons leads to markedly different transient phonon populations evident in electron diffraction patterns. This understanding of how tuning optical excitations affect phonon populations and atomic motion is critical for efficiently controlling light-induced structural transitions of optoelectronic devices.
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Affiliation(s)
- Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations , University of Southern California , Los Angeles , California 90089 , United States
| | - Ming-Fu Lin
- Linac Coherent Light Source , Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park , California 94025 , United States
- Stanford PULSE Institute , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Xiang Zhang
- Department of Materials Science and NanoEngineering , Rice University , Houston , Texas 77005 , United States
| | - Clemens Weninger
- Linac Coherent Light Source , Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park , California 94025 , United States
- Stanford PULSE Institute , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Ruru Ma
- Collaboratory for Advanced Computing and Simulations , University of Southern California , Los Angeles , California 90089 , United States
| | - Alexander Britz
- Linac Coherent Light Source , Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park , California 94025 , United States
- Stanford PULSE Institute , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Chandra Sekhar Tiwary
- Department of Materials Science and NanoEngineering , Rice University , Houston , Texas 77005 , United States
| | - Vidya Kochat
- Department of Materials Science and NanoEngineering , Rice University , Houston , Texas 77005 , United States
| | - Amey Apte
- Department of Materials Science and NanoEngineering , Rice University , Houston , Texas 77005 , United States
| | - Jie Yang
- SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Suji Park
- SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Renkai Li
- SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Xijie Wang
- SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Rajiv Kalia
- Collaboratory for Advanced Computing and Simulations , University of Southern California , Los Angeles , California 90089 , United States
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations , University of Southern California , Los Angeles , California 90089 , United States
| | - Fuyuki Shimojo
- Department of Physics , Kumamoto University , Kumamoto 860-8555 , Japan
| | - David Fritz
- Linac Coherent Light Source , Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Uwe Bergmann
- Stanford PULSE Institute , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | - Pulickel Ajayan
- Department of Materials Science and NanoEngineering , Rice University , Houston , Texas 77005 , United States
| | - Priya Vashishta
- Collaboratory for Advanced Computing and Simulations , University of Southern California , Los Angeles , California 90089 , United States
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10
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Tsai YW, Chang YY, Lee JJ, Liu WC, Wu YH, Liu WR, Liu HY, Lee KY, Weng SC, Sheu HS, Chiu MS, Lee YY, Hsu CH, Chang SL. Time-resolved X-ray reflection phases of the nearly forbidden Si(222) reflection under laser excitation. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:819-824. [PMID: 31074447 DOI: 10.1107/s1600577519003503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
The covalent electron density, which makes Si(222) measurable, is subject to laser excitation. The three-wave Si(222)/(13 {\overline 1}) diffraction at 7.82 keV is used for phase measurements. It is found that laser excitation causes a relative phase change of around 4° in Si(222) in the first 100 ps of excitation and this is gradually recovered over several nanoseconds. This phase change is due to laser excitation of covalent electrons around the silicon atoms in the unit cell and makes the electron density deviate further from the centrosymmetric distribution.
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Affiliation(s)
- Yi Wei Tsai
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Ying Yi Chang
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Jey Jau Lee
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Wen Chung Liu
- Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yu Hsin Wu
- Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu 300, Taiwan
| | - Wei Rein Liu
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Hsing Yu Liu
- Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Kun Yuan Lee
- Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Shih Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Hwo Shuenn Sheu
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Mau Sen Chiu
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Yin Yu Lee
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Chia Hung Hsu
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Shih Lin Chang
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
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11
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Tinnemann V, Streubühr C, Hafke B, Kalus A, Hanisch-Blicharski A, Ligges M, Zhou P, von der Linde D, Bovensiepen U, Horn-von Hoegen M. Ultrafast electron diffraction from a Bi(111) surface: Impulsive lattice excitation and Debye-Waller analysis at large momentum transfer. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2019; 6:035101. [PMID: 31111080 PMCID: PMC6494652 DOI: 10.1063/1.5093637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
The lattice response of a Bi(111) surface upon impulsive femtosecond laser excitation is studied with time-resolved reflection high-energy electron diffraction. We employ a Debye-Waller analysis at large momentum transfer of 9.3 Å-1 ≤ Δ k ≤ 21.8 Å-1 in order to study the lattice excitation dynamics of the Bi surface under conditions of weak optical excitation up to 2 mJ/cm2 incident pump fluence. The observed time constants τ int of decay of diffraction spot intensity depend on the momentum transfer Δk and range from 5 to 12 ps. This large variation of τ int is caused by the nonlinearity of the exponential function in the Debye-Waller factor and has to be taken into account for an intensity drop ΔI > 0.2. An analysis of more than 20 diffraction spots with a large variation in Δk gave a consistent value for the time constant τT of vibrational excitation of the surface lattice of 12 ± 1 ps independent on the excitation density. We found no evidence for a deviation from an isotropic Debye-Waller effect and conclude that the primary laser excitation leads to thermal lattice excitation, i.e., heating of the Bi surface.
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Affiliation(s)
- V Tinnemann
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - C Streubühr
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - B Hafke
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - A Kalus
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - A Hanisch-Blicharski
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - M Ligges
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - P Zhou
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - D von der Linde
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - U Bovensiepen
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
| | - M Horn-von Hoegen
- Department of Physics and Center for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg, Germany
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12
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Makita M, Vartiainen I, Mohacsi I, Caleman C, Diaz A, Jönsson HO, Juranić P, Medvedev N, Meents A, Mozzanica A, Opara NL, Padeste C, Panneels V, Saxena V, Sikorski M, Song S, Vera L, Willmott PR, Beaud P, Milne CJ, Ziaja-Motyka B, David C. Femtosecond phase-transition in hard x-ray excited bismuth. Sci Rep 2019; 9:602. [PMID: 30679456 PMCID: PMC6345934 DOI: 10.1038/s41598-018-36216-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/14/2018] [Indexed: 11/26/2022] Open
Abstract
The evolution of bismuth crystal structure upon excitation of its A1g phonon has been intensely studied with short pulse optical lasers. Here we present the first-time observation of a hard x-ray induced ultrafast phase transition in a bismuth single crystal at high intensities (~1014 W/cm2). The lattice evolution was followed using a recently demonstrated x-ray single-shot probing setup. The time evolution of the (111) Bragg peak intensity showed strong dependence on the excitation fluence. After exposure to a sufficiently intense x-ray pulse, the peak intensity dropped to zero within 300 fs, i.e. faster than one oscillation period of the A1g mode at room temperature. Our analysis indicates a nonthermal origin of a lattice disordering process, and excludes interpretations based on electron-ion equilibration process, or on thermodynamic heating process leading to plasma formation.
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Affiliation(s)
- M Makita
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.
| | - I Vartiainen
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - I Mohacsi
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.,Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - C Caleman
- CFEL, Deutsches Elektronen-Synchrotron DESY, 22607, Hamburg, Germany.,Department of Physics and Astronomy, Uppsala University, SE-751 24, Uppsala, Sweden
| | - A Diaz
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - H O Jönsson
- Department of Physics and Astronomy, Uppsala University, SE-751 24, Uppsala, Sweden.,Department of Applied physics, KTH Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - P Juranić
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - N Medvedev
- Institute of Physics, Czech Academy of Sciences, 182 21, Prague 8, Czech Republic.,Institute of Plasma Physics, Czech Academy of Sciences, 182 00, Prague 8, Czech Republic
| | - A Meents
- CFEL, Deutsches Elektronen-Synchrotron DESY, 22607, Hamburg, Germany
| | - A Mozzanica
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - N L Opara
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.,C-CINA Biozentrum, University of Basel, CH-4058, Basel, Switzerland
| | - C Padeste
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - V Panneels
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - V Saxena
- CFEL, Deutsches Elektronen-Synchrotron DESY, 22607, Hamburg, Germany.,Institute for Plasma Research, Bhat, Gandhinagar, 382428, India
| | - M Sikorski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - S Song
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - L Vera
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - P R Willmott
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - P Beaud
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - C J Milne
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - B Ziaja-Motyka
- CFEL, Deutsches Elektronen-Synchrotron DESY, 22607, Hamburg, Germany.,Institute of Nuclear Physics, Polish Academy of Sciences, 31-342, Krakow, Poland
| | - C David
- Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
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13
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Teitelbaum SW, Henighan T, Huang Y, Liu H, Jiang MP, Zhu D, Chollet M, Sato T, Murray ÉD, Fahy S, O'Mahony S, Bailey TP, Uher C, Trigo M, Reis DA. Direct Measurement of Anharmonic Decay Channels of a Coherent Phonon. PHYSICAL REVIEW LETTERS 2018; 121:125901. [PMID: 30296113 DOI: 10.1103/physrevlett.121.125901] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 02/21/2018] [Indexed: 05/23/2023]
Abstract
We report channel-resolved measurements of the anharmonic coupling of the coherent A_{1g} phonon in photoexcited bismuth to pairs of high wave vector acoustic phonons. The decay of a coherent phonon can be understood as a parametric resonance process whereby the atomic displacement periodically modulates the frequency of a broad continuum of modes. This coupling drives temporal oscillations in the phonon mean-square displacements at the A_{1g} frequency that are observed across the Brillouin zone by femtosecond x-ray diffuse scattering. We extract anharmonic coupling constants between the A_{1g} and several representative decay channels that are within an order of magnitude of density functional perturbation theory calculations.
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Affiliation(s)
- Samuel W Teitelbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Thomas Henighan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Yijing Huang
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Hanzhe Liu
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Mason P Jiang
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Diling Zhu
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Matthieu Chollet
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Takahiro Sato
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Éamonn D Murray
- Department of Physics and Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom
| | - Stephen Fahy
- Tyndall National Institute, Cork T12K8AF, Ireland
- Department of Physics, University College Cork, Cork T12K8AF, Ireland
| | - Shane O'Mahony
- Tyndall National Institute, Cork T12K8AF, Ireland
- Department of Physics, University College Cork, Cork T12K8AF, Ireland
| | - Trevor P Bailey
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ctirad Uher
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Mariano Trigo
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - David A Reis
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
- Department of Photon Science, Stanford University, Stanford, California 94305, USA
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14
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Sjakste J, Tanimura K, Barbarino G, Perfetti L, Vast N. Hot electron relaxation dynamics in semiconductors: assessing the strength of the electron-phonon coupling from the theoretical and experimental viewpoints. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:353001. [PMID: 30084390 DOI: 10.1088/1361-648x/aad487] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The rapid development of the computational methods based on density functional theory, on the one hand, and of time-, energy-, and momentum-resolved spectroscopy, on the other hand, allows today an unprecedently detailed insight into the processes governing hot-electron relaxation dynamics, and, in particular, into the role of the electron-phonon coupling. Instead of focusing on the development of a particular method, theoretical or experimental, this review aims to treat the progress in the understanding of the electron-phonon coupling which can be gained from both, on the basis of recently obtained results. We start by defining several regimes of hot electron relaxation via electron-phonon coupling, with respect to the electron excitation energy. We distinguish between energy and momentum relaxation of hot electrons, and summarize, for several semiconductors of the IV and III-V groups, the orders of magnitude of different relaxation times in different regimes, on the basis of known experimental and numerical data. Momentum relaxation times of hot electrons become very short around 1 eV above the bottom of the conduction band, and such ultrafast relaxation mechanisms are measurable only in the most recent pump-probe experiments. Then, we give an overview of the recent progress in the experimental techniques allowing to obtain detailed information on the hot-electron relaxation dynamics, with the main focus on time-, energy-, and momentum-resolved photoemission experiments. The particularities of the experimental approach developed by one of us, which allows to capture time-, energy-, and momentum-resolved hot-electron distributions, as well as to measure momentum relaxation times of the order of 10 fs, are discussed. We further discuss the main advances in the calculation of the electron-phonon scattering times from first principles over the past ten years, in semiconducting materials. Ab initio techniques and efficient interpolation methods provide the possibility to calculate electron-phonon scattering times with high precision at reasonable numerical cost. We highlight the methods of analysis of the obtained numerical results, which allow to give insight into the details of the electron-phonon scattering mechanisms. Finally, we discuss the concept of hot electron ensemble which has been proposed recently to describe the hot-electron relaxation dynamics in GaAs, the applicability of this concept to other materials, and its limitations. We also mention some open problems.
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Affiliation(s)
- J Sjakste
- Laboratoire des Solides Irradiés, Ecole Polytechnique, CEA-DRF-IRAMIS, CNRS UMR 7642, 91120 Palaiseau, France
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15
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Carbone F, Hengsberger M, Castiglioni L, Osterwalder J. Femtosecond manipulation of spins, charges, and ions in nanostructures, thin films, and surfaces. Struct Dyn 2017; 4:061504. [PMID: 29308416 PMCID: PMC5736395 DOI: 10.1063/1.4995541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/05/2017] [Indexed: 11/15/2022] Open
Affiliation(s)
- F. Carbone
- Ecole Polytechnique Fédérale de Lausanne, Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), EPFL Campus, Lausanne, Dorigny CH-1015, Switzerland
| | - M. Hengsberger
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
| | - L. Castiglioni
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
| | - J. Osterwalder
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
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16
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Abela R, Beaud P, van Bokhoven JA, Chergui M, Feurer T, Haase J, Ingold G, Johnson SL, Knopp G, Lemke H, Milne CJ, Pedrini B, Radi P, Schertler G, Standfuss J, Staub U, Patthey L. Perspective: Opportunities for ultrafast science at SwissFEL. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:061602. [PMID: 29376109 PMCID: PMC5758366 DOI: 10.1063/1.4997222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 10/17/2017] [Indexed: 05/03/2023]
Abstract
We present the main specifications of the newly constructed Swiss Free Electron Laser, SwissFEL, and explore its potential impact on ultrafast science. In light of recent achievements at current X-ray free electron lasers, we discuss the potential territory for new scientific breakthroughs offered by SwissFEL in Chemistry, Biology, and Materials Science, as well as nonlinear X-ray science.
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Affiliation(s)
- Rafael Abela
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Paul Beaud
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Jeroen A van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS), Ecole Polytechnique Fédérale de Lausanne (EPFL), ISIC-FSB, Station 6, 1015 Lausanne, Switzerland
| | - Thomas Feurer
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Johannes Haase
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Gerhard Ingold
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Steven L Johnson
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zurich, Switzerland
| | - Gregor Knopp
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Henrik Lemke
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Chris J Milne
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bill Pedrini
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Peter Radi
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | | | - Jörg Standfuss
- Division of Biology and Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Urs Staub
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Luc Patthey
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
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17
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Li Z, Inhester L, Liekhus-Schmaltz C, Curchod BFE, Snyder JW, Medvedev N, Cryan J, Osipov T, Pabst S, Vendrell O, Bucksbaum P, Martinez TJ. Ultrafast isomerization in acetylene dication after carbon K-shell ionization. Nat Commun 2017; 8:453. [PMID: 28878226 PMCID: PMC5587545 DOI: 10.1038/s41467-017-00426-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 06/28/2017] [Indexed: 11/09/2022] Open
Abstract
Ultrafast proton migration and isomerization are key processes for acetylene and its ions. However, the mechanism for ultrafast isomerization of acetylene [HCCH]2+ to vinylidene [H2CC]2+ dication remains nebulous. Theoretical studies show a large potential barrier ( > 2 eV) for isomerization on low-lying dicationic states, implying picosecond or longer isomerization timescales. However, a recent experiment at a femtosecond X-ray free-electron laser suggests sub-100 fs isomerization. Here we address this contradiction with a complete theoretical study of the dynamics of acetylene dication produced by Auger decay after X-ray photoionization of the carbon atom K shell. We find no sub-100 fs isomerization, while reproducing the salient features of the time-resolved Coulomb imaging experiment. This work resolves the seeming contradiction between experiment and theory and also calls for careful interpretation of structural information from the widely applied Coulomb momentum imaging method. The timescale of isomerization in molecules involving ultrafast migration of constituent atoms is difficult to measure. Here the authors report that sub-100 fs isomerization time on acetylene dication in lower electronic states is not possible and point to misinterpretation of recent experimental results.
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Affiliation(s)
- Zheng Li
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA.,Department of Chemistry and the PULSE Institute, Stanford University, 333 Campus Drive, Stanford, California, 94305, USA
| | - Ludger Inhester
- Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraße 85, D-22607, Hamburg, Germany.,Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, D-22761, Hamburg, Germany
| | - Chelsea Liekhus-Schmaltz
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA.,Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California, 94305, USA
| | - Basile F E Curchod
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA.,Department of Chemistry and the PULSE Institute, Stanford University, 333 Campus Drive, Stanford, California, 94305, USA
| | - James W Snyder
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA.,Department of Chemistry and the PULSE Institute, Stanford University, 333 Campus Drive, Stanford, California, 94305, USA
| | - Nikita Medvedev
- Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraße 85, D-22607, Hamburg, Germany.,Department of Radiation and Chemical Physics, Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21, Prague 8, Czech Republic.,Laser Plasma Department, Institute of Plasma Physics, Czech Academy of Sciences, Za Slovankou 3, 182 00, Prague 8, Czech Republic
| | - James Cryan
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA
| | - Timur Osipov
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA
| | - Stefan Pabst
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts, 02138, USA
| | - Oriol Vendrell
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus, Denmark
| | - Phil Bucksbaum
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA.,Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California, 94305, USA
| | - Todd J Martinez
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA. .,Department of Chemistry and the PULSE Institute, Stanford University, 333 Campus Drive, Stanford, California, 94305, USA.
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18
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Sokolowski-Tinten K, Shen X, Zheng Q, Chase T, Coffee R, Jerman M, Li RK, Ligges M, Makasyuk I, Mo M, Reid AH, Rethfeld B, Vecchione T, Weathersby SP, Dürr HA, Wang XJ. Electron-lattice energy relaxation in laser-excited thin-film Au-insulator heterostructures studied by ultrafast MeV electron diffraction. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:054501. [PMID: 28795080 PMCID: PMC5522339 DOI: 10.1063/1.4995258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/10/2017] [Indexed: 05/19/2023]
Abstract
We apply time-resolved MeV electron diffraction to study the electron-lattice energy relaxation in thin film Au-insulator heterostructures. Through precise measurements of the transient Debye-Waller-factor, the mean-square atomic displacement is directly determined, which allows to quantitatively follow the temporal evolution of the lattice temperature after short pulse laser excitation. Data obtained over an extended range of laser fluences reveal an increased relaxation rate when the film thickness is reduced or the Au-film is capped with an additional insulator top-layer. This behavior is attributed to a cross-interfacial coupling of excited electrons in the Au film to phonons in the adjacent insulator layer(s). Analysis of the data using the two-temperature-model taking explicitly into account the additional energy loss at the interface(s) allows to deduce the relative strength of the two relaxation channels.
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Affiliation(s)
- K Sokolowski-Tinten
- Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - X Shen
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - Q Zheng
- School of Materials and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China
| | - T Chase
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - R Coffee
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - M Jerman
- Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - R K Li
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - M Ligges
- Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - I Makasyuk
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - M Mo
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - A H Reid
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - B Rethfeld
- Department of Physics and OPTIMAS Research Center, Technical University Kaiserslautern, Erwin-Schrödinger-Strae 46, 67663 Kaiserslautern, Germany
| | - T Vecchione
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - S P Weathersby
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - H A Dürr
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - X J Wang
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
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19
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Papenkort T, Axt VM, Kuhn T. Stationary Phonon Squeezing by Optical Polaron Excitation. PHYSICAL REVIEW LETTERS 2017; 118:097401. [PMID: 28306296 DOI: 10.1103/physrevlett.118.097401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Indexed: 06/06/2023]
Abstract
We demonstrate that a stationary squeezed phonon state can be prepared by a pulsed optical excitation of a semiconductor quantum well. Unlike previously discussed scenarios for generating squeezed phonons, the corresponding uncertainties become stationary after the excitation and do not oscillate in time. The effect is caused by two-phonon correlations within the excited polaron. We demonstrate by quantum kinetic simulations and by a perturbation analysis that the energetically lowest polaron state comprises two-phonon correlations which, after the pulse, result in an uncertainty of the lattice momentum that is continuously lower than in the ground state of the semiconductor. The simulations show the dynamics of the polaron formation process and the resulting time-dependent lattice uncertainties.
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Affiliation(s)
- T Papenkort
- Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - V M Axt
- Institut für Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany
| | - T Kuhn
- Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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20
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Haghshenasfard Z, Cottam MG. Quantum statistics and squeezing for a microwave-driven interacting magnon system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:045803. [PMID: 27897145 DOI: 10.1088/1361-648x/29/4/045803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Theoretical studies are reported for the statistical properties of a microwave-driven interacting magnon system. Both the magnetic dipole-dipole and the exchange interactions are included and the theory is developed for the case of parallel pumping allowing for the inclusion of the nonlinear processes due to the four-magnon interactions. The method of second quantization is used to transform the total Hamiltonian from spin operators to boson creation and annihilation operators. By using the coherent magnon state representation we have studied the magnon occupation number and the statistical behavior of the system. In particular, it is shown that the nonlinearities introduced by the parallel pumping field and the four-magnon interactions lead to non-classical quantum statistical properties of the system, such as magnon squeezing. Also control of the collapse-and-revival phenomena for the time evolution of the average magnon number is demonstrated by varying the parallel pumping amplitude and the four-magnon coupling.
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Affiliation(s)
- Zahra Haghshenasfard
- Department of Physics and Astronomy, The University of Western Ontario, London, Ontario N6A 3K7, Canada
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21
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Somma C, Folpini G, Reimann K, Woerner M, Elsaesser T. Two-Phonon Quantum Coherences in Indium Antimonide Studied by Nonlinear Two-Dimensional Terahertz Spectroscopy. PHYSICAL REVIEW LETTERS 2016; 116:177401. [PMID: 27176538 DOI: 10.1103/physrevlett.116.177401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 06/05/2023]
Abstract
We report the first observation of two-phonon quantum coherences in a semiconductor. Two-dimensional terahertz (THz) spectra recorded with a sequence of three THz pulses display strong two-phonon signals, clearly distinguished from signals due to interband two-photon absorption and electron tunneling. The two-phonon coherences originate from impulsive off-resonant excitation in the nonperturbative regime of light-matter interaction. A theoretical analysis provides the relevant Liouville pathways, showing that nonlinear interactions using the large interband dipole moment generate stronger two-phonon excitations than linear interactions.
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Affiliation(s)
- Carmine Somma
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Giulia Folpini
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Klaus Reimann
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Michael Woerner
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Thomas Elsaesser
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
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22
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Photon number statistics uncover the fluctuations in non-equilibrium lattice dynamics. Nat Commun 2015; 6:10249. [PMID: 26690958 PMCID: PMC4703887 DOI: 10.1038/ncomms10249] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/19/2015] [Indexed: 11/08/2022] Open
Abstract
Fluctuations of the atomic positions are at the core of a large class of unusual material properties ranging from quantum para-electricity to high temperature superconductivity. Their measurement in solids is the subject of an intense scientific debate focused on seeking a methodology capable of establishing a direct link between the variance of the atomic displacements and experimentally measurable observables. Here we address this issue by means of non-equilibrium optical experiments performed in shot-noise-limited regime. The variance of the time-dependent atomic positions and momenta is directly mapped into the quantum fluctuations of the photon number of the scattered probing light. A fully quantum description of the non-linear interaction between photonic and phononic fields is benchmarked by unveiling the squeezing of thermal phonons in α-quartz.
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Singla R, Cotugno G, Kaiser S, Först M, Mitrano M, Liu HY, Cartella A, Manzoni C, Okamoto H, Hasegawa T, Clark SR, Jaksch D, Cavalleri A. THz-Frequency Modulation of the Hubbard U in an Organic Mott Insulator. PHYSICAL REVIEW LETTERS 2015; 115:187401. [PMID: 26565494 DOI: 10.1103/physrevlett.115.187401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Indexed: 06/05/2023]
Abstract
We use midinfrared pulses with stable carrier-envelope phase offset to drive molecular vibrations in the charge transfer salt ET-F_{2}TCNQ, a prototypical one-dimensional Mott insulator. We find that the Mott gap, which is probed resonantly with 10 fs laser pulses, oscillates with the pump field. This observation reveals that molecular excitations can coherently perturb the electronic on-site interactions (Hubbard U) by changing the local orbital wave function. The gap oscillates at twice the frequency of the vibrational mode, indicating that the molecular distortions couple quadratically to the local charge density.
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Affiliation(s)
- R Singla
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - G Cotugno
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, OX1 3PU Oxford, United Kingdom
| | - S Kaiser
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
| | - M Först
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - M Mitrano
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - H Y Liu
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - A Cartella
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - C Manzoni
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- IFN-CNR, Dipartimento di Fisica-Politecnico di Milano, Milan, Italy
| | - H Okamoto
- Department of Advanced Material Science, University of Tokyo, Chiba 277-8561, Japan
| | - T Hasegawa
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8562, Japan
| | - S R Clark
- Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, OX1 3PU Oxford, United Kingdom
- Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - D Jaksch
- Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, OX1 3PU Oxford, United Kingdom
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - A Cavalleri
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, OX1 3PU Oxford, United Kingdom
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van der Veen RM, Penfold TJ, Zewail AH. Ultrafast core-loss spectroscopy in four-dimensional electron microscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:024302. [PMID: 26798793 PMCID: PMC4711615 DOI: 10.1063/1.4916897] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 03/23/2015] [Indexed: 05/06/2023]
Abstract
We demonstrate ultrafast core-electron energy-loss spectroscopy in four-dimensional electron microscopy as an element-specific probe of nanoscale dynamics. We apply it to the study of photoexcited graphite with femtosecond and nanosecond resolutions. The transient core-loss spectra, in combination with ab initio molecular dynamics simulations, reveal the elongation of the carbon-carbon bonds, even though the overall behavior is a contraction of the crystal lattice. A prompt energy-gap shrinkage is observed on the picosecond time scale, which is caused by local bond length elongation and the direct renormalization of band energies due to temperature-dependent electron-phonon interactions.
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Affiliation(s)
| | - Thomas J Penfold
- SwissFEL, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland
| | - Ahmed H Zewail
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology , Pasadena, California 91125, USA
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25
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Squeezed Phonon Wave Packet Generation by Optical Manipulation of a Quantum Dot. PHOTONICS 2015. [DOI: 10.3390/photonics2010214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Elsaesser T, Woerner M. Perspective: structural dynamics in condensed matter mapped by femtosecond x-ray diffraction. J Chem Phys 2014; 140:020901. [PMID: 24437858 DOI: 10.1063/1.4855115] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Ultrashort soft and hard x-ray pulses are sensitive probes of structural dynamics on the picometer length and femtosecond time scales of electronic and atomic motions. Recent progress in generating such pulses has initiated new directions of condensed matter research, exploiting a variety of x-ray absorption, scattering, and diffraction methods to probe photoinduced structural dynamics. Atomic motion, changes of local structure and long-range order, as well as correlated electron motion and charge transfer have been resolved in space and time, providing a most direct access to the physical mechanisms and interactions driving reversible and irreversible changes of structure. This perspective combines an overview of recent advances in femtosecond x-ray diffraction with a discussion on ongoing and future developments.
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Affiliation(s)
- T Elsaesser
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - M Woerner
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
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Leuenberger D, Yanagisawa H, Roth S, Dil JH, Wells JW, Hofmann P, Osterwalder J, Hengsberger M. Excitation of coherent phonons in the one-dimensional Bi(114) surface. PHYSICAL REVIEW LETTERS 2013; 110:136806. [PMID: 23581358 DOI: 10.1103/physrevlett.110.136806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Indexed: 06/02/2023]
Abstract
We present time-resolved photoemission experiments from a peculiar bismuth surface, Bi(114). The strong one-dimensional character of this surface is reflected in the Fermi surface, which consists of spin-polarized straight lines. Our results show that the depletion of the surface state and the population of the bulk conduction band after the initial optical excitation persist for very long times. The disequilibrium within the hot electron gas along with strong electron-phonon coupling cause a displacive excitation of coherent phonons, which in turn are reflected in coherent modulations of the electronic states. Beside the well-known A(1g) bulk phonon mode at 2.76 THz, the time-resolved photoelectron spectra reveal a second mode at 0.72 THz which can be attributed to an optical surface phonon mode along the atomic rows of the Bi(114) surface.
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Affiliation(s)
- D Leuenberger
- Physics Institute, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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31
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Arnaud B, Giret Y. Electron cooling and debye-waller effect in photoexcited bismuth. PHYSICAL REVIEW LETTERS 2013; 110:016405. [PMID: 23383816 DOI: 10.1103/physrevlett.110.016405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Indexed: 06/01/2023]
Abstract
By means of first principles calculations, we compute the effective electron-phonon coupling constant G(0) governing the electron cooling in photoexcited bismuth. G(0) strongly increases as a function of electron temperature, which can be traced back to the semimetallic nature of bismuth. We also use a thermodynamical model to compute the time evolution of both electron and lattice temperatures following laser excitation. Thereby, we simulate the time evolution of (1 -1 0), (-2 1 1) and (2 -2 0) Bragg peak intensities measured by Sciaini et al. [Nature (London) 458, 56 (2009)] in femtosecond electron diffraction experiments. The effect of the electron temperature on the Debye-Waller factors through the softening of all optical modes across the whole Brillouin zone turns out to be crucial to reproduce the time evolution of these Bragg peak intensities.
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Affiliation(s)
- B Arnaud
- Institut de Physique de Rennes, UMR UR1-CNRS 6251, Campus de Beaulieu-Bat 11 A, 35042 Rennes Cedex, France
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Wall S, Wegkamp D, Foglia L, Appavoo K, Nag J, Haglund RF, Stähler J, Wolf M. Ultrafast changes in lattice symmetry probed by coherent phonons. Nat Commun 2012; 3:721. [PMID: 22395612 DOI: 10.1038/ncomms1719] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 02/01/2012] [Indexed: 11/09/2022] Open
Abstract
The electronic and structural properties of a material are strongly determined by its symmetry. Changing the symmetry via a photoinduced phase transition offers new ways to manipulate material properties on ultrafast timescales. However, to identify when and how fast these phase transitions occur, methods that can probe the symmetry change in the time domain are required. Here we show that a time-dependent change in the coherent phonon spectrum can probe a change in symmetry of the lattice potential, thus providing an all-optical probe of structural transitions. We examine the photoinduced structural phase transition in VO(2) and show that, above the phase transition threshold, photoexcitation completely changes the lattice potential on an ultrafast timescale. The loss of the equilibrium-phase phonon modes occurs promptly, indicating a non-thermal pathway for the photoinduced phase transition, where a strong perturbation to the lattice potential changes its symmetry before ionic rearrangement has occurred.
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Affiliation(s)
- S Wall
- Department of Physical Chemistry, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, Berlin 14195, Germany.
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Johnson SL, de Souza RA, Staub U, Beaud P, Möhr-Vorobeva E, Ingold G, Caviezel A, Scagnoli V, Schlotter WF, Turner JJ, Krupin O, Lee WS, Chuang YD, Patthey L, Moore RG, Lu D, Yi M, Kirchmann PS, Trigo M, Denes P, Doering D, Hussain Z, Shen ZX, Prabhakaran D, Boothroyd AT. Femtosecond dynamics of the collinear-to-spiral antiferromagnetic phase transition in CuO. PHYSICAL REVIEW LETTERS 2012; 108:037203. [PMID: 22400779 DOI: 10.1103/physrevlett.108.037203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Indexed: 05/19/2023]
Abstract
We report on the ultrafast dynamics of magnetic order in a single crystal of CuO at a temperature of 207 K in response to strong optical excitation using femtosecond resonant x-ray diffraction. In the experiment, a femtosecond laser pulse induces a sudden, nonequilibrium increase in magnetic disorder. After a short delay ranging from 400 fs to 2 ps, we observe changes in the relative intensity of the magnetic ordering diffraction peaks that indicate a shift from a collinear commensurate phase to a spiral incommensurate phase. These results indicate that the ultimate speed for this antiferromagnetic reorientation transition in CuO is limited by the long-wavelength magnetic excitation connecting the two phases.
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Affiliation(s)
- S L Johnson
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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Carbone F, Musumeci P, Luiten O, Hebert C. A perspective on novel sources of ultrashort electron and X-ray pulses. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.10.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Freyer B, Stingl J, Zamponi F, Woerner M, Elsaesser T. The rotating-crystal method in femtosecond X-ray diffraction. OPTICS EXPRESS 2011; 19:15506-15515. [PMID: 21934913 DOI: 10.1364/oe.19.015506] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We report the first implementation of the rotating-crystal method in femtosecond X-ray diffraction. Applying a pump-probe scheme with 100 fs hard X-ray probe pulses from a laser-driven plasma source, the novel technique is demonstrated by mapping structural dynamics of a photoexcited bismuth crystal via changes of the diffracted intensity on a multitude of Bragg reflections. The method is compared to femtosecond powder diffraction and to Bragg diffraction from a crystal with stationary orientation.
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Affiliation(s)
- B Freyer
- Max-Born-Institut f¨ur Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany.
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36
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Giret Y, Gellé A, Arnaud B. Entropy driven atomic motion in laser-excited bismuth. PHYSICAL REVIEW LETTERS 2011; 106:155503. [PMID: 21568573 DOI: 10.1103/physrevlett.106.155503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Indexed: 05/06/2023]
Abstract
We introduce a thermodynamical model based on the two-temperature approach in order to fully understand the dynamics of the coherent A(1g) phonon in laser-excited bismuth. Using this model, we simulate the time evolution of (111) Bragg peak intensities measured by Fritz et al. [Science 315, 633 (2007)] in femtosecond x-ray diffraction experiments performed on a bismuth film for different laser fluences. The agreement between theoretical and experimental results is striking not only because we use fluences very close to the experimental ones but also because most of the model parameters are obtained from ab initio calculations performed for different electron temperatures.
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Affiliation(s)
- Y Giret
- Institut de Physique de Rennes, UMR UR1-CNRS 6251, Campus de Beaulieu-Bat 11 A, 35042 Rennes Cedex, France, EU
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Snapshots of cooperative atomic motions in the optical suppression of charge density waves. Nature 2010; 468:799-802. [PMID: 21107321 DOI: 10.1038/nature09539] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 09/24/2010] [Indexed: 11/08/2022]
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Sauer S, Daniels JM, Reiter DE, Kuhn T, Vagov A, Axt VM. Lattice fluctuations at a double phonon frequency with and without squeezing: an exactly solvable model of an optically excited quantum dot. PHYSICAL REVIEW LETTERS 2010; 105:157401. [PMID: 21230936 DOI: 10.1103/physrevlett.105.157401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Indexed: 05/30/2023]
Abstract
Time-dependent lattice fluctuations of an optically excited strongly confined quantum dot are investigated with the aim to analyze the characteristics commonly used for identifying the presence of squeezed phonon states. It is demonstrated that the appearance of fluctuations oscillating with twice the phonon frequency, commonly regarded as a clear indication of squeezed states, cannot be considered as such. The source of the discrepancy with earlier investigations is discussed. Conditions for generating a squeezed state by using a two-pulse excitation are analyzed.
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Affiliation(s)
- S Sauer
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany
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Woerner M, Zamponi F, Ansari Z, Dreyer J, Freyer B, Prémont-Schwarz M, Elsaesser T. Concerted electron and proton transfer in ionic crystals mapped by femtosecond x-ray powder diffraction. J Chem Phys 2010; 133:064509. [DOI: 10.1063/1.3469779] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Miller RJD, Ernstorfer R, Harb M, Gao M, Hebeisen CT, Jean-Ruel H, Lu C, Moriena G, Sciaini G. `Making the molecular movie': first frames. Acta Crystallogr A 2010; 66:137-56. [DOI: 10.1107/s0108767309053926] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 12/14/2009] [Indexed: 11/10/2022] Open
Abstract
Recent advances in high-intensity electron and X-ray pulsed sources now make it possible to directly observe atomic motions as they occur in barrier-crossing processes. These rare events require the structural dynamics to be triggered by femtosecond excitation pulses that prepare the system above the barrier or access new potential energy surfaces that drive the structural changes. In general, the sampling process modifies the system such that the structural probes should ideally have sufficient intensity to fully resolve structures near the single-shot limit for a given time point. New developments in both source intensity and temporal characterization of the pulsed sampling mode have made it possible to make so-called `molecular movies',i.e.measure relative atomic motions faster than collisions can blur information on correlations. Strongly driven phase transitions from thermally propagated melting to optically modified potential energy surfaces leading to ballistic phase transitions and bond stiffening are given as examples of the new insights that can be gained from an atomic level perspective of structural dynamics. The most important impact will likely be made in the fields of chemistry and biology where the central unifying concept of the transition state will come under direct observation and enable a reduction of high-dimensional complex reaction surfaces to the key reactive modes, as long mastered by Mother Nature.
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Johnson SL, Beaud P, Vorobeva E, Milne CJ, Murray ÉD, Fahy S, Ingold G. Non-equilibrium phonon dynamics studied by grazing-incidence femtosecond X-ray crystallography. Acta Crystallogr A 2010; 66:157-67. [DOI: 10.1107/s0108767309053859] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 12/14/2009] [Indexed: 11/10/2022] Open
Abstract
The timescales for structural changes in a single crystal of bismuth after excitation with an intense near-infrared laser pulse are studied with femtosecond pump-probe X-ray diffraction. Changes in the intensity and reciprocal-lattice vector of several reflections give quantitative information on the structure factor and lattice strain as a function of time, with a resolution of 200 fs. The results indicate that the majority of excess carrier energy that remains near the surface is transferred to vibrational modes on a timescale of about 10 ps, and that the resultant increase in the variance of the atomic positions at these times is consistent with the overall magnitude of lattice strain that develops.
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Zijlstra ES, Díaz-Sánchez LE, Garcia ME. Comment on "Directly observing squeezed phonon states with femtosecond X-ray diffraction". PHYSICAL REVIEW LETTERS 2010; 104:029601-029602. [PMID: 20366629 DOI: 10.1103/physrevlett.104.029601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Indexed: 05/29/2023]
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43
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Johnson SL, Vorobeva E, Beaud P, Milne CJ, Ingold G. Full reconstruction of a crystal unit cell structure during coherent femtosecond motion. PHYSICAL REVIEW LETTERS 2009; 103:205501. [PMID: 20365989 DOI: 10.1103/physrevlett.103.205501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Indexed: 05/29/2023]
Abstract
We present a complete characterization of the unit cell dynamics of a laser-excited tellurium crystal using femtosecond x-ray diffraction. The analysis offers a quantitative measure of the unit cell dynamics without making any assumptions on the symmetry of the excited-state motion. The results show a large-amplitude coherently excited A(1) mode quantitatively consistent with the predictions of a density functional theory model.
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Affiliation(s)
- S L Johnson
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
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Beaud P, Johnson SL, Vorobeva E, Staub U, De Souza RA, Milne CJ, Jia QX, Ingold G. Ultrafast structural phase transition driven by photoinduced melting of charge and orbital order. PHYSICAL REVIEW LETTERS 2009; 103:155702. [PMID: 19905651 DOI: 10.1103/physrevlett.103.155702] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 09/14/2009] [Indexed: 05/19/2023]
Abstract
We use femtosecond x-ray diffraction to probe directly the structural dynamics of a charge ordered and orbitally ordered thin film of La0.42Ca0.58MnO3 initiated by an ultrafast optical pulse. At low excitation fluences we observe the displacive excitation of a coherent optical A(g) phonon. Under high excitation conditions we observe a complete phase transition within 1 ps via the disappearance of a superlattice reflection. The initial step of the phase transition occurs on a time scale significantly faster than the 200 fs time resolution of our experiment.
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Affiliation(s)
- P Beaud
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
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