1
|
Huber M, Lin Y, Marini G, Moreschini L, Jozwiak C, Bostwick A, Calandra M, Lanzara A. Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe 2. SCIENCE ADVANCES 2024; 10:eadl4481. [PMID: 38728393 PMCID: PMC11086600 DOI: 10.1126/sciadv.adl4481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024]
Abstract
Screening, a ubiquitous phenomenon associated with the shielding of electric fields by surrounding charges, has been widely adopted as a means to modify a material's properties. While most studies have relied on static changes of screening through doping or gating thus far, here we demonstrate that screening can also drive the onset of distinct quantum states on the ultrafast timescale. By using time- and angle-resolved photoemission spectroscopy, we show that intense optical excitation can drive 1T-TiSe2, a prototypical charge density wave material, almost instantly from a gapped into a semimetallic state. By systematically comparing changes in band structure over time and excitation strength with theoretical calculations, we find that the appearance of this state is likely caused by a dramatic reduction of the screening length. In summary, this work showcases how optical excitation enables the screening-driven design of a nonequilibrium semimetallic phase in TiSe2, possibly providing a general pathway into highly screened phases in other strongly correlated materials.
Collapse
Affiliation(s)
- Maximilian Huber
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yi Lin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Giovanni Marini
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, I-16163 Genova, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
| | - Luca Moreschini
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matteo Calandra
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, I-16163 Genova, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
- Sorbonne Universite, CNRS, Institut des Nanosciences de Paris, F-75252 Paris, France
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Physics Department, University of California, Berkeley, Berkeley, CA 94720, USA
- Kavli Energy NanoScience Institute, Berkeley, CA 94720, USA
| |
Collapse
|
2
|
Hwang J, Ruan W, Chen Y, Tang S, Crommie MF, Shen ZX, Mo SK. Charge density waves in two-dimensional transition metal dichalcogenides. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:044502. [PMID: 38518359 DOI: 10.1088/1361-6633/ad36d3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Charge density wave (CDW is one of the most ubiquitous electronic orders in quantum materials. While the essential ingredients of CDW order have been extensively studied, a comprehensive microscopic understanding is yet to be reached. Recent research efforts on the CDW phenomena in two-dimensional (2D) materials provide a new pathway toward a deeper understanding of its complexity. This review provides an overview of the CDW orders in 2D with atomically thin transition metal dichalcogenides (TMDCs) as the materials platform. We mainly focus on the electronic structure investigations on the epitaxially grown TMDC samples with angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy as complementary experimental tools. We discuss the possible origins of the 2D CDW, novel quantum states coexisting with them, and exotic types of charge orders that can only be realized in the 2D limit.
Collapse
Affiliation(s)
- Jinwoong Hwang
- Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Wei Ruan
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, People's Republic of China
| | - Yi Chen
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, People's Republic of China
| | - Shujie Tang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
| | - Michael F Crommie
- Department of Physics, University of California, Berkeley, CA, United States of America
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
- Kavli Energy NanoSciences Institute at the University of California at Berkeley, Berkeley, CA 94720, United States of America
| | - Zhi-Xun Shen
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA, United States of America
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, United States of America
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 United States of America
| |
Collapse
|
3
|
Knispel T, Berges J, Schobert A, van Loon EGCP, Jolie W, Wehling T, Michely T, Fischer J. Unconventional Charge-Density-Wave Gap in Monolayer NbS 2. NANO LETTERS 2024; 24:1045-1051. [PMID: 38232959 PMCID: PMC10835735 DOI: 10.1021/acs.nanolett.3c02787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Using scanning tunneling microscopy and spectroscopy, for a monolayer of transition metal dichalcogenide H-NbS2 grown by molecular beam epitaxy on graphene, we provide unambiguous evidence for a charge density wave (CDW) with a 3 × 3 superstructure, which is not present in bulk NbS2. Local spectroscopy displays a pronounced gap on the order of 20 meV at the Fermi level. Within the gap, low-energy features are present. The gap structure with its low-energy features is at variance with the expectation for a gap opening in the electronic band structure due to a CDW. Instead, comparison with ab initio calculations indicates that the observed gap structure must be attributed to combined electron-phonon quasiparticles. The phonons in question are the elusive amplitude and phase collective modes of the CDW transition. Our findings advance the understanding of CDW mechanisms in 2D materials and their spectroscopic signatures.
Collapse
Affiliation(s)
- Timo Knispel
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - Jan Berges
- U Bremen Excellence Chair, Bremen Center for Computational Materials Science, and MAPEX Center for Materials and Processes, University of Bremen, D-28359 Bremen, Germany
| | - Arne Schobert
- I. Institute of Theoretical Physics, Universität Hamburg, D-22607 Hamburg, Germany
| | - Erik G C P van Loon
- NanoLund and Division of Mathematical Physics, Department of Physics, Lund University, SE-22100 Lund, Sweden
| | - Wouter Jolie
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - Tim Wehling
- I. Institute of Theoretical Physics, Universität Hamburg, D-22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| | - Jeison Fischer
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany
| |
Collapse
|
4
|
Pan M, Liu J, Chen F, Wang J, Yun C, Qian T. Time-resolved ARPES with probe energy of 6.0/7.2 eV and switchable resolution configuration. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:013001. [PMID: 38165821 DOI: 10.1063/5.0177361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 12/09/2023] [Indexed: 01/04/2024]
Abstract
We present a detailed exposition of the design for time- and angle-resolved photoemission spectroscopy using a UV probe laser source that combines the nonlinear effects of β-BaB2O4 and KBe2BO3F2 optical crystals. The photon energy of the probe laser can be switched between 6.0 and 7.2 eV, with the flexibility to operate each photon energy setting under two distinct resolution configurations. Under the fully optimized energy resolution configuration, we achieve an energy resolution of 8.5 meV at 6.0 eV and 10 meV at 7.2 eV. Alternatively, switching to the other configuration enhances the temporal resolution, yielding a temporal resolution of 72 fs for 6.0 eV and 185 fs for 7.2 eV. We validated the performance and reliability of our system by applying it to measuring two typical materials: the topological insulator MnBi2Te4 and the excitonic insulator candidate Ta2NiSe5.
Collapse
Affiliation(s)
- Mojun Pan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junde Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Famin Chen
- Southern University of Science and Technology, Shenzhen 518055, China
| | - Ji Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Chenxia Yun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Tian Qian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|
5
|
Guan M, Chen D, Chen Q, Yao Y, Meng S. Coherent Phonon Assisted Ultrafast Order-Parameter Reversal and Hidden Metallic State in Ta_{2}NiSe_{5}. PHYSICAL REVIEW LETTERS 2023; 131:256503. [PMID: 38181365 DOI: 10.1103/physrevlett.131.256503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/20/2023] [Accepted: 12/01/2023] [Indexed: 01/07/2024]
Abstract
The nonequilibrium dynamics during photoinduced insulator-to-metal transition (IMT) in the excitonic insulator (EI) candidate Ta_{2}NiSe_{5} have been investigated, which reproduce the timescale and spectral features of the ultrafast switch and reveal intricate many-body interactions involving multidegrees of freedom. The key role of lattice order parameter (OP) reversal, occurring on a timescale comparable to that of purely electronic processes (<100 fs), is identified. This reversal is enabled by the anharmonic interactions between EI-OP-coupled phonons and the conventional coherent phonons, leading to a modified potential energy landscape and a high-frequency mode up-conversion. The phonon excitation depends on the dynamics of photocarriers distributed around the Fermi level, and thus intertwines with the excitonic quenching and the complete gap collapse. These findings provide a comprehensive understanding of exciton-phonon dynamics in correlated quantum materials.
Collapse
Affiliation(s)
- Mengxue Guan
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, 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
- 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
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, 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
|
6
|
Jung J, Jin KH, Kim J, Yeom HW. Control over a Wide Phase Diagram of 2D Correlated Electrons by Surface Doping; K/1 T-TaS 2. NANO LETTERS 2023; 23:8029-8034. [PMID: 37651727 DOI: 10.1021/acs.nanolett.3c02003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
We demonstrate the systematic tuning of a trivial insulator into a Mott insulator and a Mott insulator into a correlated metallic and a pseudogap state, which emerge in a quasi-two-dimensional electronic system of 1T-TaS2 through strong electron correlation. The band structure evolution is investigated upon surface doping by alkali adsorbates for two distinct phases occurring at around 220 and 10 K by angle-resolved photoelectron spectroscopy. We find contrasting behaviors upon doping that corroborate the fundamental difference of two electronic states: while the antibonding state of the spin-singlet insulator at 10 K is partially occupied to produce an emerging Mott insulating state, the presumed Mott insulating state at 220 K evolves into a correlated metallic state and then a pseudogap state. The work indicates that surface doping onto correlated 2D materials can be a powerful tool to systematically engineer a wide range of correlated electronic phases.
Collapse
Affiliation(s)
- Jiwon Jung
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Jaeyoung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| |
Collapse
|
7
|
Baldini E, Zong A, Choi D, Lee C, Michael MH, Windgaetter L, Mazin II, Latini S, Azoury D, Lv B, Kogar A, Su Y, Wang Y, Lu Y, Takayama T, Takagi H, Millis AJ, Rubio A, Demler E, Gedik N. The spontaneous symmetry breaking in Ta 2NiSe 5 is structural in nature. Proc Natl Acad Sci U S A 2023; 120:e2221688120. [PMID: 37071679 PMCID: PMC10151608 DOI: 10.1073/pnas.2221688120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/24/2023] [Indexed: 04/19/2023] Open
Abstract
The excitonic insulator is an electronically driven phase of matter that emerges upon the spontaneous formation and Bose condensation of excitons. Detecting this exotic order in candidate materials is a subject of paramount importance, as the size of the excitonic gap in the band structure establishes the potential of this collective state for superfluid energy transport. However, the identification of this phase in real solids is hindered by the coexistence of a structural order parameter with the same symmetry as the excitonic order. Only a few materials are currently believed to host a dominant excitonic phase, Ta2NiSe5 being the most promising. Here, we test this scenario by using an ultrashort laser pulse to quench the broken-symmetry phase of this transition metal chalcogenide. Tracking the dynamics of the material's electronic and crystal structure after light excitation reveals spectroscopic fingerprints that are compatible only with a primary order parameter of phononic nature. We rationalize our findings through state-of-the-art calculations, confirming that the structural order accounts for most of the gap opening. Our results suggest that the spontaneous symmetry breaking in Ta2NiSe5 is mostly of structural character, hampering the possibility to realize quasi-dissipationless energy transport.
Collapse
Affiliation(s)
- Edoardo Baldini
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Alfred Zong
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Dongsung Choi
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Changmin Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | | | - Lukas Windgaetter
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg22761, Germany
| | - Igor I. Mazin
- Department of Physics and Astronomy and Center for Quantum Materials, George Mason University, Fairfax, VA22030
| | - Simone Latini
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg22761, Germany
| | - Doron Azoury
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Baiqing Lv
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Anshul Kogar
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Yifan Su
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Yao Wang
- Department of Physics and Astronomy, Clemson University, Clemson, SC29631
| | - Yangfan Lu
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo113-0033, Japan
| | - Tomohiro Takayama
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo113-0033, Japan
- Max Planck Institute for Solid State Research, Stuttgart70569, Germany
| | - Hidenori Takagi
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo113-0033, Japan
- Max Planck Institute for Solid State Research, Stuttgart70569, Germany
| | - Andrew J. Millis
- Department of Physics, Columbia University, New York, NY10027
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY10010
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg22761, Germany
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY10010
- Nano-Bio Spectroscopy Group, Departamento de Física de Materiales, Universidad del País Vasco, San Sebastían20018, Spain
| | - Eugene Demler
- Department of Physics, Harvard University, Cambridge, MA02138
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| |
Collapse
|
8
|
Rajpurohit S, Simoni J, Tan LZ. Photo-induced phase-transitions in complex solids. NANOSCALE ADVANCES 2022; 4:4997-5008. [PMID: 36504738 PMCID: PMC9680828 DOI: 10.1039/d2na00481j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/01/2022] [Indexed: 06/17/2023]
Abstract
Photo-induced phase-transitions (PIPTs) driven by highly cooperative interactions are of fundamental interest as they offer a way to tune and control material properties on ultrafast timescales. Due to strong correlations and interactions, complex quantum materials host several fascinating PIPTs such as light-induced charge density waves and ferroelectricity and have become a desirable setting for studying these PIPTs. A central issue in this field is the proper understanding of the underlying mechanisms driving the PIPTs. As these PIPTs are highly nonlinear processes and often involve multiple time and length scales, different theoretical approaches are often needed to understand the underlying mechanisms. In this review, we present a brief overview of PIPTs realized in complex materials, followed by a discussion of the available theoretical methods with selected examples of recent progress in understanding of the nonequilibrium pathways of PIPTs.
Collapse
Affiliation(s)
| | - Jacopo Simoni
- Molecular Foundry, Lawrence Berkeley National Laboratory USA
| | - Liang Z Tan
- Molecular Foundry, Lawrence Berkeley National Laboratory USA
| |
Collapse
|
9
|
Huber M, Lin Y, Dale N, Sailus R, Tongay S, Kaindl RA, Lanzara A. Revealing the order parameter dynamics of 1T-TiSe[Formula: see text] following optical excitation. Sci Rep 2022; 12:15860. [PMID: 36151110 PMCID: PMC9508156 DOI: 10.1038/s41598-022-19319-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/26/2022] [Indexed: 11/09/2022] Open
Abstract
The formation of a charge density wave state is characterized by an order parameter. The way it is established provides unique information on both the role that correlation plays in driving the charge density wave formation and the mechanism behind its formation. Here we use time and angle resolved photoelectron spectroscopy to optically perturb the charge-density phase in 1T-TiSe[Formula: see text] and follow the recovery of its order parameter as a function of energy, momentum and excitation density. Our results reveal that two distinct orders contribute to the gap formation, a CDW order and pseudogap-like order, manifested by an overall robustness to optical excitation. A detailed analysis of the magnitude of the the gap as a function of excitation density and delay time reveals the excitonic long-range nature of the CDW gap and the short-range Jahn-Teller character of the pseudogap order. In contrast to the gap, the intensity of the folded Se[Formula: see text]* band can only give access to the excitonic order. These results provide new information into the the long standing debate on the origin of the gap in TiSe[Formula: see text] and place it in the same context of other quantum materials where a pseudogap phase appears to be a precursor of long-range order.
Collapse
Affiliation(s)
- Maximilian Huber
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Yi Lin
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Nicholas Dale
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Physics Department, University of California Berkeley, Berkeley, CA 94720 USA
| | - Renee Sailus
- Materials Science and Engineering Department, Arizona State University, Phoenix, AZ 85281 USA
| | - Sefaattin Tongay
- Materials Science and Engineering Department, Arizona State University, Phoenix, AZ 85281 USA
| | - Robert A. Kaindl
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Department of Physics and CXFEL Labs, Arizona State University, Phoenix, AZ 85287 USA
| | - Alessandra Lanzara
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Physics Department, University of California Berkeley, Berkeley, CA 94720 USA
| |
Collapse
|
10
|
Borrego-Varillas R, Lucchini M, Nisoli M. Attosecond spectroscopy for the investigation of ultrafast dynamics in atomic, molecular and solid-state physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:066401. [PMID: 35294930 DOI: 10.1088/1361-6633/ac5e7f] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Since the first demonstration of the generation of attosecond pulses (1 as = 10-18s) in the extreme-ultraviolet spectral region, several measurement techniques have been introduced, at the beginning for the temporal characterization of the pulses, and immediately after for the investigation of electronic and nuclear ultrafast dynamics in atoms, molecules and solids with unprecedented temporal resolution. The attosecond spectroscopic tools established in the last two decades, together with the development of sophisticated theoretical methods for the interpretation of the experimental outcomes, allowed to unravel and investigate physical processes never observed before, such as the delay in photoemission from atoms and solids, the motion of electrons in molecules after prompt ionization which precede any notable nuclear motion, the temporal evolution of the tunneling process in dielectrics, and many others. This review focused on applications of attosecond techniques to the investigation of ultrafast processes in atoms, molecules and solids. Thanks to the introduction and ongoing developments of new spectroscopic techniques, the attosecond science is rapidly moving towards the investigation, understanding and control of coupled electron-nuclear dynamics in increasingly complex systems, with ever more accurate and complete investigation techniques. Here we will review the most common techniques presenting the latest results in atoms, molecules and solids.
Collapse
Affiliation(s)
- Rocío Borrego-Varillas
- Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche (CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Matteo Lucchini
- Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche (CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Mauro Nisoli
- Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche (CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| |
Collapse
|
11
|
Guo Q, Dendzik M, Grubišić-Čabo A, Berntsen MH, Li C, Chen W, Matta B, Starke U, Hessmo B, Weissenrieder J, Tjernberg O. A narrow bandwidth extreme ultra-violet light source for time- and angle-resolved photoemission spectroscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2022; 9:024304. [PMID: 35540107 PMCID: PMC9054270 DOI: 10.1063/4.0000149] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/06/2022] [Indexed: 06/01/2023]
Abstract
Here, we present a high repetition rate, narrow bandwidth, extreme ultraviolet photon source for time- and angle-resolved photoemission spectroscopy. The narrow bandwidth pulses Δ E = 9 , 14 , and 18 meV for photon energies h ν = 10.8 , 18.1 , and 25.3 eV are generated through high harmonic generation using ultra-violet drive pulses with relatively long pulse lengths (461 fs). The high harmonic generation setup employs an annular drive beam in tight focusing geometry at a repetition rate of 250 kHz. Photon energy selection is provided by a series of selectable multilayer bandpass mirrors and thin film filters, thus avoiding any time broadening introduced by single grating monochromators. A two stage optical-parametric amplifier provides < 100 fs tunable pump pulses from 0.65 μm to 9 μm. The narrow bandwidth performance of the light source is demonstrated through angle-resolved photoemission measurements on a series of quantum materials, including high-temperature superconductor Bi-2212, WSe2, and graphene.
Collapse
Affiliation(s)
- Qinda Guo
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Maciej Dendzik
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Antonija Grubišić-Čabo
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Magnus H. Berntsen
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Cong Li
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Wanyu Chen
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Bharti Matta
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Ulrich Starke
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Björn Hessmo
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Jonas Weissenrieder
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - Oscar Tjernberg
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| |
Collapse
|
12
|
Reisbick SA, Zhang Y, Chen J, Engen PE, Flannigan DJ. Coherent Phonon Disruption and Lock-In during a Photoinduced Charge-Density-Wave Phase Transition. J Phys Chem Lett 2021; 12:6439-6447. [PMID: 34236194 DOI: 10.1021/acs.jpclett.1c01673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ultrafast manipulation of phase domains in quantum materials is a promising approach to unraveling and harnessing interwoven charge and lattice degrees of freedom. Here we find evidence for coupling of displacively excited coherent acoustic phonons (CAPs) and periodic lattice distortions (PLDs) in the intensely studied charge-density-wave material, 1T-TaS2, using 4D ultrafast electron microscopy (UEM). Initial photoinduced Bragg-peak dynamics reveal partial CAP coherence and localized c-axis dilations. Weak, partially coherent dynamics give way to higher-amplitude, increasingly coherent oscillations, the transition period of which matches that of photoinduced incommensurate domain growth and stabilization from the nearly-commensurate phase. With UEM imaging, it is found that phonon wave trains emerge from linear defects 100 ps after photoexcitation. The CAPs consist of coupled longitudinal and transverse character and propagate at anomalously high velocities along wave vectors independent from PLDs, instead being dictated by defect orientation. Such behaviors illustrate a means to control phases in quantum materials using defect-engineered coherent-phonon seeding.
Collapse
Affiliation(s)
- Spencer A Reisbick
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Yichao Zhang
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Jialiang Chen
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Paige E Engen
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
13
|
Ravnik J, Diego M, Gerasimenko Y, Vaskivskyi Y, Vaskivskyi I, Mertelj T, Vodeb J, Mihailovic D. A time-domain phase diagram of metastable states in a charge ordered quantum material. Nat Commun 2021; 12:2323. [PMID: 33875669 PMCID: PMC8055663 DOI: 10.1038/s41467-021-22646-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/17/2021] [Indexed: 11/11/2022] Open
Abstract
Metastable self-organized electronic states in quantum materials are of fundamental importance, displaying emergent dynamical properties that may be used in new generations of sensors and memory devices. Such states are typically formed through phase transitions under non-equilibrium conditions and the final state is reached through processes that span a large range of timescales. Conventionally, phase diagrams of materials are thought of as static, without temporal evolution. However, many functional properties of materials arise as a result of complex temporal changes in the material occurring on different timescales. Hitherto, such properties were not considered within the context of a temporally-evolving phase diagram, even though, under non-equilibrium conditions, different phases typically evolve on different timescales. Here, by using time-resolved optical techniques and femtosecond-pulse-excited scanning tunneling microscopy (STM), we track the evolution of the metastable states in a material that has been of wide recent interest, the quasi-two-dimensional dichalcogenide 1T-TaS2. We map out its temporal phase diagram using the photon density and temperature as control parameters on timescales ranging from 10−12 to 103 s. The introduction of a time-domain axis in the phase diagram enables us to follow the evolution of metastable emergent states created by different phase transition mechanisms on different timescales, thus enabling comparison with theoretical predictions of the phase diagram, and opening the way to understanding of the complex ordering processes in metastable materials. Tracking the evolution of non-equilibrium phases requires measurements over a wide range of timescales. Here, using a combination of femtosecond spectroscopy and scanning tunneling microscopy, the authors map out a temporal phase diagram of metastable states in a charge-ordered material 1T-TaS2.
Collapse
Affiliation(s)
- Jan Ravnik
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia.,Laboratory for Micro and Nanotechnology, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Michele Diego
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Yaroslav Gerasimenko
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia.,Center of Excellence on Nanoscience and Nanotechnology-Nanocenter (CENN Nanocenter), Ljubljana, Slovenia
| | | | - Igor Vaskivskyi
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia.,Center of Excellence on Nanoscience and Nanotechnology-Nanocenter (CENN Nanocenter), Ljubljana, Slovenia
| | - Tomaz Mertelj
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia.,Center of Excellence on Nanoscience and Nanotechnology-Nanocenter (CENN Nanocenter), Ljubljana, Slovenia
| | - Jaka Vodeb
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Dragan Mihailovic
- Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia. .,Center of Excellence on Nanoscience and Nanotechnology-Nanocenter (CENN Nanocenter), Ljubljana, Slovenia. .,Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia.
| |
Collapse
|
14
|
Bretscher HM, Andrich P, Telang P, Singh A, Harnagea L, Sood AK, Rao A. Ultrafast melting and recovery of collective order in the excitonic insulator Ta 2NiSe 5. Nat Commun 2021; 12:1699. [PMID: 33727541 PMCID: PMC7966769 DOI: 10.1038/s41467-021-21929-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/08/2021] [Indexed: 01/05/2023] Open
Abstract
The layered chalcogenide Ta2NiSe5 has been proposed to host an excitonic condensate in its ground state, a phase that could offer a unique platform to study and manipulate many-body states at room temperature. However, identifying the dominant microscopic contribution to the observed spontaneous symmetry breaking remains challenging, perpetuating the debate over the ground state properties. Here, using broadband ultrafast spectroscopy we investigate the out-of-equilibrium dynamics of Ta2NiSe5 and demonstrate that the transient reflectivity in the near-infrared range is connected to the system's low-energy physics. We track the status of the ordered phase using this optical signature, establishing that high-fluence photoexcitations can suppress this order. From the sub-50 fs quenching timescale and the behaviour of the photoinduced coherent phonon modes, we conclude that electronic correlations provide a decisive contribution to the excitonic order formation. Our results pave the way towards the ultrafast control of an exciton condensate at room temperature.
Collapse
Affiliation(s)
| | - Paolo Andrich
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Prachi Telang
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - Anupam Singh
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - Luminita Harnagea
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - A K Sood
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| |
Collapse
|
15
|
Biswas D, Jones AJH, Majchrzak P, Choi BK, Lee TH, Volckaert K, Feng J, Marković I, Andreatta F, Kang CJ, Kim HJ, Lee IH, Jozwiak C, Rotenberg E, Bostwick A, Sanders CE, Zhang Y, Karras G, Chapman RT, Wyatt AS, Springate E, Miwa JA, Hofmann P, King PDC, Chang YJ, Lanatà N, Ulstrup S. Ultrafast Triggering of Insulator-Metal Transition in Two-Dimensional VSe 2. NANO LETTERS 2021; 21:1968-1975. [PMID: 33600187 DOI: 10.1021/acs.nanolett.0c04409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The transition-metal dichalcogenide VSe2 exhibits an increased charge density wave transition temperature and an emerging insulating phase when thinned to a single layer. Here, we investigate the interplay of electronic and lattice degrees of freedom that underpin these phases in single-layer VSe2 using ultrafast pump-probe photoemission spectroscopy. In the insulating state, we observe a light-induced closure of the energy gap, which we disentangle from the ensuing hot carrier dynamics by fitting a model spectral function to the time-dependent photoemission intensity. This procedure leads to an estimated time scale of 480 fs for the closure of the gap, which suggests that the phase transition in single-layer VSe2 is driven by electron-lattice interactions rather than by Mott-like electronic effects. The ultrafast optical switching of these interactions in SL VSe2 demonstrates the potential for controlling phase transitions in 2D materials with light.
Collapse
Affiliation(s)
- Deepnarayan Biswas
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - Alfred J H Jones
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - Paulina Majchrzak
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Byoung Ki Choi
- Department of Physics, University of Seoul, Seoul 02504, Republic of Korea
| | - Tsung-Han Lee
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856, United States
| | - Klara Volckaert
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - Jiagui Feng
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, U.K
- Suzhou Institute of Nano-Tech. and Nanobionics (SINANO), CAS, 398 Ruoshui Road, SEID, SIP, Suzhou 215123, China
| | - Igor Marković
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, U.K
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Federico Andreatta
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - Chang-Jong Kang
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856, United States
| | - Hyuk Jin Kim
- Department of Physics, University of Seoul, Seoul 02504, Republic of Korea
| | - In Hak Lee
- Department of Physics, University of Seoul, Seoul 02504, Republic of Korea
| | - Chris Jozwiak
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Eli Rotenberg
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Aaron Bostwick
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Charlotte E Sanders
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Yu Zhang
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Gabriel Karras
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Richard T Chapman
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Adam S Wyatt
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Emma Springate
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell 0 × 11 0QX, U.K
| | - Jill A Miwa
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - Phil D C King
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, U.K
| | - Young Jun Chang
- Department of Physics, University of Seoul, Seoul 02504, Republic of Korea
- Department of Smart Cities, University of Seoul, Seoul, 02504, Republic of Korea
| | - Nicola Lanatà
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, 10691 Stockholm, Sweden
| | - Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| |
Collapse
|
16
|
Yang LX, Rohde G, Hanff K, Stange A, Xiong R, Shi J, Bauer M, Rossnagel K. Bypassing the Structural Bottleneck in the Ultrafast Melting of Electronic Order. PHYSICAL REVIEW LETTERS 2020; 125:266402. [PMID: 33449703 DOI: 10.1103/physrevlett.125.266402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Impulsive optical excitation generally results in a complex nonequilibrium electron and lattice dynamics that involves multiple processes on distinct timescales, and a common conception is that for times shorter than about 100 fs the gap in the electronic spectrum is not seriously affected by lattice vibrations. Here, however, by directly monitoring the photoinduced collapse of the spectral gap in a canonical charge-density-wave material, the blue bronze Rb_{0.3}MoO_{3}, we find that ultrafast (∼60 fs) vibrational disordering due to efficient hot-electron energy dissipation quenches the gap significantly faster than the typical structural bottleneck time corresponding to one half-cycle oscillation (∼315 fs) of the coherent charge-density-wave amplitude mode. This result not only demonstrates the importance of incoherent lattice motion in the photoinduced quenching of electronic order, but also resolves the perennial debate about the nature of the spectral gap in a coupled electron-lattice system.
Collapse
Affiliation(s)
- L X Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
- Frontier Science Center for Quantum Information, Beijing 100084, People's Republic of China
| | - G Rohde
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - K Hanff
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - A Stange
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - R Xiong
- Department of Physics, Wuhan University, Wuhan 430072, People's Republic of China
| | - J Shi
- Department of Physics, Wuhan University, Wuhan 430072, People's Republic of China
| | - M Bauer
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - K Rossnagel
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
- Ruprecht-Haensel-Labor, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| |
Collapse
|
17
|
Gao J, Park JW, Kim K, Song SK, Park HR, Lee J, Park J, Chen F, Luo X, Sun Y, Yeom HW. Pseudogap and Weak Multifractality in 2D Disordered Mott Charge-Density-Wave Insulator. NANO LETTERS 2020; 20:6299-6305. [PMID: 32787162 DOI: 10.1021/acs.nanolett.0c01607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigate electronic states of Se-substituted 1T-TaS2 by scanning tunneling microscopy/spectroscopy (STM/STS), where superconductivity emerges from the unique Mott-charge-density-wave (Mott-CDW) state. Spatially resolved STS measurements reveal that a pseudogap replaces the Mott gap with the CDW gaps intact. The pseudogap has little correlation with the unit-cell-to-unit-cell variation in the local Se concentration but appears globally. The correlation length of the local density of states (LDOS) is substantially enhanced at the Fermi energy and decays rapidly at high energies. Furthermore, the statistical analysis of LDOS indicates the weak multifractal behavior of the wave functions. These findings suggest a correlated metallic state induced by disorder and provide a new insight into the emerging superconductivity in two-dimensional materials.
Collapse
Affiliation(s)
- Jianhua Gao
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
| | - Jae Whan Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
| | - Kiseok Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sun Kyu Song
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Hae Ryong Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Jhinhwan Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
| | - Jewook Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
| | - Fangchu Chen
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Xuan Luo
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Yuping Sun
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| |
Collapse
|
18
|
You P, Chen D, Lian C, Zhang C, Meng S. First‐principles dynamics of photoexcited molecules and materials towards a quantum description. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2020. [DOI: 10.1002/wcms.1492] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Peiwei You
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing China
| | - Daqiang Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing China
| | - Chao Lian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
| | - Cui Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
- Songshan Lake Materials Laboratory Dongguan China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing China
- Songshan Lake Materials Laboratory Dongguan China
| |
Collapse
|
19
|
Keunecke M, Möller C, Schmitt D, Nolte H, Jansen GSM, Reutzel M, Gutberlet M, Halasi G, Steil D, Steil S, Mathias S. Time-resolved momentum microscopy with a 1 MHz high-harmonic extreme ultraviolet beamline. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:063905. [PMID: 32611056 DOI: 10.1063/5.0006531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Recent progress in laser-based high-repetition rate extreme ultraviolet (EUV) light sources and multidimensional photoelectron spectroscopy enables the build-up of a new generation of time-resolved photoemission experiments. Here, we present a setup for time-resolved momentum microscopy driven by a 1 MHz fs EUV table-top light source optimized for the generation of 26.5 eV photons. The setup provides simultaneous access to the temporal evolution of the photoelectron's kinetic energy and in-plane momentum. We discuss opportunities and limitations of our new experiment based on a series of static and time-resolved measurements on graphene.
Collapse
Affiliation(s)
- Marius Keunecke
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Christina Möller
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - David Schmitt
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hendrik Nolte
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - G S Matthijs Jansen
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Marcel Reutzel
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Marie Gutberlet
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Gyula Halasi
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Daniel Steil
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Sabine Steil
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Stefan Mathias
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| |
Collapse
|
20
|
Storeck G, Horstmann JG, Diekmann T, Vogelgesang S, von Witte G, Yalunin SV, Rossnagel K, Ropers C. Structural dynamics of incommensurate charge-density waves tracked by ultrafast low-energy electron diffraction. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:034304. [PMID: 32596414 PMCID: PMC7311179 DOI: 10.1063/4.0000018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
We study the non-equilibrium structural dynamics of the incommensurate and nearly commensurate charge-density wave (CDW) phases in 1T-TaS 2 . Employing ultrafast low-energy electron diffraction with 1 ps temporal resolution, we investigate the ultrafast quench and recovery of the CDW-coupled periodic lattice distortion (PLD). Sequential structural relaxation processes are observed by tracking the intensities of main lattice as well as satellite diffraction peaks and the diffuse scattering background. Comparing distinct groups of diffraction peaks, we disentangle the ultrafast quench of the PLD amplitude from phonon-related reductions of the diffraction intensity. Fluence-dependent relaxation cycles reveal a long-lived partial suppression of the order parameter for up to 60 ps, far outlasting the initial amplitude recovery and electron-phonon scattering times. This delayed return to a quasi-thermal level is controlled by lattice thermalization and coincides with the population of zone-center acoustic modes, as evidenced by a structured diffuse background. The long-lived non-equilibrium order parameter suppression suggests hot populations of CDW-coupled lattice modes. Finally, a broadening of the superlattice peaks is observed at high fluences, pointing to a non-linear generation of phase fluctuations.
Collapse
Affiliation(s)
- G. Storeck
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - J. G. Horstmann
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - T. Diekmann
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - S. Vogelgesang
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - G. von Witte
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - S. V. Yalunin
- 4th Physical Institute, Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | | | - C. Ropers
- Author to whom correspondence should be addressed:
| |
Collapse
|
21
|
Coherent modulation of the electron temperature and electron-phonon couplings in a 2D material. Proc Natl Acad Sci U S A 2020; 117:8788-8793. [PMID: 32241890 DOI: 10.1073/pnas.1917341117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ultrashort light pulses can selectively excite charges, spins, and phonons in materials, providing a powerful approach for manipulating their properties. Here we use femtosecond laser pulses to coherently manipulate the electron and phonon distributions, and their couplings, in the charge-density wave (CDW) material 1T-TaSe2 After exciting the material with a femtosecond pulse, fast spatial smearing of the laser-excited electrons launches a coherent lattice breathing mode, which in turn modulates the electron temperature. This finding is in contrast to all previous observations in multiple materials to date, where the electron temperature decreases monotonically via electron-phonon scattering. By tuning the laser fluence, the magnitude of the electron temperature modulation changes from ∼200 K in the case of weak excitation, to ∼1,000 K for strong laser excitation. We also observe a phase change of π in the electron temperature modulation at a critical fluence of 0.7 mJ/cm2, which suggests a switching of the dominant coupling mechanism between the coherent phonon and electrons. Our approach opens up routes for coherently manipulating the interactions and properties of two-dimensional and other quantum materials using light.
Collapse
|
22
|
Lee C, Rohwer T, Sie EJ, Zong A, Baldini E, Straquadine J, Walmsley P, Gardner D, Lee YS, Fisher IR, Gedik N. High resolution time- and angle-resolved photoemission spectroscopy with 11 eV laser pulses. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:043102. [PMID: 32357712 DOI: 10.1063/1.5139556] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/18/2020] [Indexed: 06/11/2023]
Abstract
Performing time- and angle-resolved photoemission (tr-ARPES) spectroscopy at high momenta necessitates extreme ultraviolet laser pulses, which are typically produced via high harmonic generation (HHG). Despite recent advances, HHG-based setups still require large pulse energies (from hundreds of μJ to mJ) and their energy resolution is limited to tens of meV. Here, we present a novel 11 eV tr-ARPES setup that generates a flux of 5 × 1010 photons/s and achieves an unprecedented energy resolution of 16 meV. It can be operated at high repetition rates (up to 250 kHz) while using input pulse energies down to 3 µJ. We demonstrate these unique capabilities by simultaneously capturing the energy and momentum resolved dynamics in two well-separated momentum space regions of a charge density wave material ErTe3. This novel setup offers the opportunity to study the non-equilibrium band structure of solids with exceptional energy and time resolutions at high repetition rates.
Collapse
Affiliation(s)
- Changmin Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Timm Rohwer
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Edbert J Sie
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Alfred Zong
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Edoardo Baldini
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Joshua Straquadine
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Philip Walmsley
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Dillon Gardner
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Young S Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Ian R Fisher
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| |
Collapse
|
23
|
Cucini R, Pincelli T, Panaccione G, Kopic D, Frassetto F, Miotti P, Pierantozzi GM, Peli S, Fondacaro A, De Luisa A, De Vita A, Carrara P, Krizmancic D, Payne DT, Salvador F, Sterzi A, Poletto L, Parmigiani F, Rossi G, Cilento F. Coherent narrowband light source for ultrafast photoelectron spectroscopy in the 17-31 eV photon energy range. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:014303. [PMID: 32039283 PMCID: PMC6994270 DOI: 10.1063/1.5131216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/13/2020] [Indexed: 05/25/2023]
Abstract
Here, we report on a novel narrowband High Harmonic Generation (HHG) light source designed for ultrafast photoelectron spectroscopy (PES) on solids. Notably, at 16.9 eV photon energy, the harmonics bandwidth equals 19 meV. This result has been obtained by seeding the HHG process with 230 fs pulses at 515 nm. The ultimate energy resolution achieved on a polycrystalline Au sample at 40 K is ∼22 meV at 16.9 eV. These parameters set a new benchmark for narrowband HHG sources and have been obtained by varying the repetition rate up to 200 kHz and, consequently, mitigating the space charge, operating with ≈ 3 × 10 7 electrons/s and ≈ 5 × 10 8 photons/s. By comparing the harmonics bandwidth and the ultimate energy resolution with a pulse duration of ∼105 fs (as retrieved from time-resolved experiments on bismuth selenide), we demonstrate a new route for ultrafast space-charge-free PES experiments on solids close to transform-limit conditions.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Simone Peli
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste, Italy
| | | | | | - Alessandro De Vita
- Dipartimento di Fisica, Università di Milano, via Celoria 16, Milano, Italy
| | - Pietro Carrara
- Dipartimento di Fisica, Università di Milano, via Celoria 16, Milano, Italy
| | | | - Daniel T. Payne
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste, Italy
| | | | - Andrea Sterzi
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste, Italy
| | | | | | | | - Federico Cilento
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste, Italy
| |
Collapse
|
24
|
Treacher DJ, Lloyd DT, Wiegandt F, O'Keeffe K, Hooker SM. Optimised XUV holography using spatially shaped high harmonic beams. OPTICS EXPRESS 2019; 27:29016-29025. [PMID: 31684643 DOI: 10.1364/oe.27.029016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
We present a novel method for controlling the transverse positions and relative powers of multiple high-order harmonic beams. A phase-only spatial light modulator is used to produce multiple infrared foci, the positions and intensities of which can be controlled programmably, enabling the generation and control of multiple HHG beams. To demonstrate the utility of this method we perform Fourier transform holography with separate illumination of the object and reference pinhole by a pair of HHG beams, which makes optimal use of the available photon flux. The programmable control of the spatial distribution of HHG beams demonstrated here offers new opportunities for experiments at extreme ultraviolet (XUV) wavelengths, particularly for photon intensive applications such as imaging.
Collapse
|
25
|
Zhang J, Lian C, Guan M, Ma W, Fu H, Guo H, Meng S. Photoexcitation Induced Quantum Dynamics of Charge Density Wave and Emergence of a Collective Mode in 1 T-TaS 2. NANO LETTERS 2019; 19:6027-6034. [PMID: 31416307 DOI: 10.1021/acs.nanolett.9b01865] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Photoexcitation is a powerful means in distinguishing different interactions and manipulating the states of matter, especially in charge density wave (CDW) materials. The CDW state of 1T-TaS2 has been widely studied experimentally mainly because of its intriguing laser-induced ultrafast responses of electronic and lattice subsystems. However, the microscopic atomic dynamics and underlying electronic mechanism upon photoexcitation remain unclear. Here, we demonstrate photoexcitation induced ultrafast dynamics of CDW in 1T-TaS2 using time-dependent density functional theory molecular dynamics. We discover a novel collective oscillation mode between the CDW state and a transient state induced by photodoping, which is significantly different from thermally induced phonon mode and attributed to the modification of the potential energy surface from laser excitation. In addition, our finding validates nonthermal melting of CDW induced at low light intensities, supporting that conventional hot electron model is inadequate to explain photoinduced dynamics. Our results provide a deep insight into the coherent electron and lattice quantum dynamics during the formation and excitation of CDW in 1T-TaS2.
Collapse
Affiliation(s)
- Jin Zhang
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Chao Lian
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
| | - Mengxue Guan
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Wei Ma
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Huixia Fu
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Haizhong Guo
- School of Physics and Engineering , Zhengzhou University , Zhengzhou , Henan 450001 , P. R. China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
- Songshan Lake Materials Laboratory , Dongguan , Guangdong 523808 , P. R. China
| |
Collapse
|
26
|
Sie EJ, Rohwer T, Lee C, Gedik N. Time-resolved XUV ARPES with tunable 24-33 eV laser pulses at 30 meV resolution. Nat Commun 2019; 10:3535. [PMID: 31388015 PMCID: PMC6684652 DOI: 10.1038/s41467-019-11492-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 07/15/2019] [Indexed: 11/09/2022] Open
Abstract
High harmonic generation of ultrafast laser pulses can be used to perform angle-resolved photoemission spectroscopy (ARPES) to map the electronic band structure of materials with femtosecond time resolution. However, currently it is difficult to reach high momenta with narrow energy resolution. Here, we combine a gas phase extreme ultraviolet (XUV) femtosecond light source, an XUV monochromator, and a time-of-flight electron analyzer to develop XUV-based time-resolved ARPES. Our technique can produce tunable photon energy between 24-33 eV with an unprecedented energy resolution of 30 meV and time resolution of 200 fs. This technique enables time-, energy- and momentum-resolved investigation of the nonequilibrium dynamics of electrons in materials with a full access to their first Brillouin zone. We evaluate the performance of this setup through exemplary measurements on various quantum materials, including WTe2, WSe2, TiSe2, and Bi2Sr2CaCu2O8+δ.
Collapse
Affiliation(s)
- Edbert J Sie
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Timm Rohwer
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Changmin Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| |
Collapse
|
27
|
Chávez-Cervantes M, Topp GE, Aeschlimann S, Krause R, Sato SA, Sentef MA, Gierz I. Charge Density Wave Melting in One-Dimensional Wires with Femtosecond Subgap Excitation. PHYSICAL REVIEW LETTERS 2019; 123:036405. [PMID: 31386485 DOI: 10.1103/physrevlett.123.036405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 05/16/2019] [Indexed: 06/10/2023]
Abstract
Charge density waves (CDWs) are symmetry-broken ground states that commonly occur in low-dimensional metals due to strong electron-electron and/or electron-phonon coupling. The nonequilibrium carrier distribution established via photodoping with femtosecond laser pulses readily quenches these ground states and induces an ultrafast insulator-to-metal phase transition. To date, CDW melting has been mainly investigated in the single-photon regime with pump photon energies bigger than the gap size. The recent development of strong-field midinfrared sources now enables the investigation of CDW dynamics following subgap excitation. Here we excite prototypical one-dimensional indium wires with a CDW gap of ∼300 meV with midinfrared pulses at ℏω=190 meV with MV/cm field strength and probe the transient electronic structure with time- and angle-resolved photoemission spectroscopy. We find that the CDW gap is filled on a timescale short compared to our temporal resolution of 300 fs and that the band structure changes are completed within ∼1 ps. Supported by a minimal theoretical model we attribute our findings to multiphoton absorption across the CDW gap.
Collapse
Affiliation(s)
- M Chávez-Cervantes
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - G E Topp
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - S Aeschlimann
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - R Krause
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - S A Sato
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - I Gierz
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg 22761, Germany
| |
Collapse
|
28
|
Yang Y, Tang T, Duan S, Zhou C, Hao D, Zhang W. A time- and angle-resolved photoemission spectroscopy with probe photon energy up to 6.7 eV. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:063905. [PMID: 31254991 DOI: 10.1063/1.5090439] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/04/2019] [Indexed: 06/09/2023]
Abstract
We present the development of a time- and angle-resolved photoemission spectroscopy based on a Yb-based femtosecond laser and a hemispherical electron analyzer. The energy of the pump photon is tunable between 1.4 and 1.9 eV, and the pulse duration is around 30 fs. We use a KBe2BO3F2 nonlinear optical crystal to generate probe pulses, of which the photon energy is up to 6.7 eV, and obtain an overall time resolution of 1 ps and energy resolution of 18 meV. In addition, β-BaB2O4 crystals are used to generate alternative probe pulses at 6.05 eV, giving an overall time resolution of 130 fs and energy resolution of 19 meV. We illustrate the performance of the system with representative data on several samples (Bi2Se3, YbCd2Sb2, and FeSe).
Collapse
Affiliation(s)
- Yuanyuan Yang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tianwei Tang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shaofeng Duan
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chaocheng Zhou
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Duxing Hao
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wentao Zhang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| |
Collapse
|
29
|
Abstract
A review that summarizes the most recent technological developments in the field of ultrafast structural dynamics with focus on the use of ultrashort X-ray and electron pulses follows. Atomistic views of chemical processes and phase transformations have long been the exclusive domain of computer simulators. The advent of femtosecond (fs) hard X-ray and fs-electron diffraction techniques made it possible to bring such a level of scrutiny to the experimental area. The following review article provides a summary of the main ultrafast techniques that enabled the generation of atomically resolved movies utilizing ultrashort X-ray and electron pulses. Recent advances are discussed with emphasis on synchrotron-based methods, tabletop fs-X-ray plasma sources, ultrabright fs-electron diffractometers, and timing techniques developed to further improve the temporal resolution and fully exploit the use of intense and ultrashort X-ray free electron laser (XFEL) pulses.
Collapse
|
30
|
Shi X, You W, Zhang Y, Tao Z, Oppeneer PM, Wu X, Thomale R, Rossnagel K, Bauer M, Kapteyn H, Murnane M. Ultrafast electron calorimetry uncovers a new long-lived metastable state in 1 T-TaSe 2 mediated by mode-selective electron-phonon coupling. SCIENCE ADVANCES 2019; 5:eaav4449. [PMID: 30838333 PMCID: PMC6397029 DOI: 10.1126/sciadv.aav4449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
Quantum materials represent one of the most promising frontiers in the quest for faster, lightweight, energy-efficient technologies. However, their inherent complexity and rich phase landscape make them challenging to understand or manipulate. Here, we present a new ultrafast electron calorimetry technique that can systematically uncover new phases of quantum matter. Using time- and angle-resolved photoemission spectroscopy, we measure the dynamic electron temperature, band structure, and heat capacity. This approach allows us to uncover a new long-lived metastable state in the charge density wave material 1T-TaSe2, which is distinct from all the known equilibrium phases: It is characterized by a substantially reduced effective total heat capacity that is only 30% of the normal value, because of selective electron-phonon coupling to a subset of phonon modes. As a result, less energy is required to melt the charge order and transform the state of the material than under thermal equilibrium conditions.
Collapse
Affiliation(s)
- Xun Shi
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Wenjing You
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Yingchao Zhang
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Zhensheng Tao
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Peter M. Oppeneer
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Xianxin Wu
- Institut fur Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Ronny Thomale
- Institut fur Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Kai Rossnagel
- Institute of Experimental and Applied Physics, Kiel University, D-24098 Kiel, Germany
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
- Ruprecht Haensel Laboratory, Kiel University and DESY, D-24098 Kiel and D-22607 Hamburg, Germany
| | - Michael Bauer
- Institute of Experimental and Applied Physics, Kiel University, D-24098 Kiel, Germany
| | - Henry Kapteyn
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Margaret Murnane
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| |
Collapse
|
31
|
Directional sub-femtosecond charge transfer dynamics and the dimensionality of 1T-TaS 2. Sci Rep 2019; 9:488. [PMID: 30679501 PMCID: PMC6346016 DOI: 10.1038/s41598-018-36637-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 11/25/2018] [Indexed: 11/19/2022] Open
Abstract
For the layered transition metal dichalcogenide 1T-TaS2, we establish through a unique experimental approach and density functional theory, how ultrafast charge transfer in 1T-TaS2 takes on isotropic three-dimensional character or anisotropic two-dimensional character, depending on the commensurability of the charge density wave phases of 1T-TaS2. The X-ray spectroscopic core-hole-clock method prepares selectively in- and out-of-plane polarized sulfur 3p orbital occupation with respect to the 1T-TaS2 planes and monitors sub-femtosecond wave packet delocalization. Despite being a prototypical two-dimensional material, isotropic three-dimensional charge transfer is found in the commensurate charge density wave phase (CCDW), indicating strong coupling between layers. In contrast, anisotropic two-dimensional charge transfer occurs for the nearly commensurate phase (NCDW). In direct comparison, theory shows that interlayer interaction in the CCDW phase – not layer stacking variations – causes isotropic three-dimensional charge transfer. This is presumably a general mechanism for phase transitions and tailored properties of dichalcogenides with charge density waves.
Collapse
|
32
|
Spin-ARPES EUV Beamline for Ultrafast Materials Research and Development. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new femtosecond, Extreme Ultraviolet (EUV), Time Resolved Spin-Angle Resolved Photo-Emission Spectroscopy (TR-Spin-ARPES) beamline was developed for ultrafast materials research and development. This 50-fs laser-driven, table-top beamline is an integral part of the “Ultrafast Spintronic Materials Facility”, dedicated to engineering ultrafast materials. This facility provides a fast and in-situ analysis and development of new materials. The EUV source based on high harmonic generation process emits 2.3 × 1011 photons/second (2.3 × 108 photons/pulse) at H23 (35.7 eV) and its photon energy ranges from 10 eV to 75 eV, which enables surface sensitive studies of the electronic structure dynamics. The EUV monochromator provides the narrow bandwidth of the EUV beamline while preserving its pulse duration in an energy range of 10–100 eV. Ultrafast surface photovoltaic effect with ~650 fs rise-time was observed in p-GaAs (100) from time-resolved ARPES spectra. The data acquisition time could be reduced by over two orders of magnitude by scaling the laser driver from 1 KHz, 4W to MHz, KW average power.
Collapse
|
33
|
Excitation and Relaxation Dynamics of the Photo-Perturbed Correlated Electron System 1T-TaS2. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app9010044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We investigate the perturbation and subsequent recovery of the correlated electronic ground state of the Mott insulator 1T-TaS 2 by means of femtosecond time-resolved photoemission spectroscopy in normal emission geometry. Upon an increase of near-infrared excitation strength, a considerable collapse of the occupied Hubbard band is observed, which reflects a quench of short-range correlations. It is furthermore found that these excitations are directly linked to the lifting of the periodic lattice distortion which provides the localization centers for the formation of the insulating Mott state. We discuss the observed dynamics in a localized real-space picture.
Collapse
|
34
|
Mang MM, Lloyd DT, Anderson PN, Treacher D, Wyatt AS, Hooker SM, Walmsley IA, O'Keeffe K. Spatially resolved common-path high-order harmonic interferometry. OPTICS LETTERS 2018; 43:5275-5278. [PMID: 30382986 DOI: 10.1364/ol.43.005275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
Spatially resolved interference is observed between high-order harmonics generated in two longitudinally separated gas targets. High-contrast modulations in the intensity of each harmonic order up to the cutoff are observed on-axis in the far field of the source as the separation between the gas targets is increased. For low-order harmonics, additional off-axis modulations are observed, which are attributed to the interference between the contributions from the long quantum trajectories from each gas target. The inherent synchronization of this setup offers the prospect for high-stability metrology of quantum states with ultrafast temporal resolutions.
Collapse
|
35
|
Ideta SI, Zhang D, Dijkstra AG, Artyukhin S, Keskin S, Cingolani R, Shimojima T, Ishizaka K, Ishii H, Kudo K, Nohara M, Miller RJD. Ultrafast dissolution and creation of bonds in IrTe 2 induced by photodoping. SCIENCE ADVANCES 2018; 4:eaar3867. [PMID: 30062122 PMCID: PMC6063536 DOI: 10.1126/sciadv.aar3867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
The observation and control of interweaving spin, charge, orbital, and structural degrees of freedom in materials on ultrafast time scales reveal exotic quantum phenomena and enable new active forms of nanotechnology. Bonding is the prime example of the relation between electronic and nuclear degrees of freedom. We report direct evidence illustrating that photoexcitation can be used for ultrafast control of the breaking and recovery of bonds in solids on unprecedented time scales, near the limit for nuclear motions. We describe experimental and theoretical studies of IrTe2 using femtosecond electron diffraction and density functional theory to investigate bonding instability. Ir-Ir dimerization shows an unexpected fast dissociation and recovery due to the filling of the antibonding dxy orbital. Bond length changes of 20% in IrTe2 are achieved by effectively addressing the bonds directly through this relaxation process. These results could pave the way to ultrafast switching between metastable structures by photoinduced manipulation of the relative degree of bonding in this manner.
Collapse
Affiliation(s)
- Shin-ichiro Ideta
- Max Planck Institute for the Structure and Dynamics of Matter, and Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
- Quantum-Phase Electronics Center, Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| | - Dongfang Zhang
- Max Planck Institute for the Structure and Dynamics of Matter, and Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Arend G. Dijkstra
- Max Planck Institute for the Structure and Dynamics of Matter, and Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
- School of Chemistry and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Sergey Artyukhin
- Italian Institute of Technology, Via Morego, 30, 16163 Genova, Italy
| | - Sercan Keskin
- Max Planck Institute for the Structure and Dynamics of Matter, and Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Roberto Cingolani
- Italian Institute of Technology, Via Morego, 30, 16163 Genova, Italy
| | - Takahiro Shimojima
- Quantum-Phase Electronics Center, Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| | - Kyoko Ishizaka
- Quantum-Phase Electronics Center, Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| | - Hiroyuki Ishii
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Kazutaka Kudo
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Minoru Nohara
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - R. J. Dwayne Miller
- Max Planck Institute for the Structure and Dynamics of Matter, and Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
- Departments of Chemistry and Physics, 80 St. George Street, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| |
Collapse
|
36
|
Zhou X, He S, Liu G, Zhao L, Yu L, Zhang W. New developments in laser-based photoemission spectroscopy and its scientific applications: a key issues review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:062101. [PMID: 29460857 DOI: 10.1088/1361-6633/aab0cc] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The significant progress in angle-resolved photoemission spectroscopy (ARPES) in last three decades has elevated it from a traditional band mapping tool to a precise probe of many-body interactions and dynamics of quasiparticles in complex quantum systems. The recent developments of deep ultraviolet (DUV, including ultraviolet and vacuum ultraviolet) laser-based ARPES have further pushed this technique to a new level. In this paper, we review some latest developments in DUV laser-based photoemission systems, including the super-high energy and momentum resolution ARPES, the spin-resolved ARPES, the time-of-flight ARPES, and the time-resolved ARPES. We also highlight some scientific applications in the study of electronic structure in unconventional superconductors and topological materials using these state-of-the-art DUV laser-based ARPES. Finally we provide our perspectives on the future directions in the development of laser-based photoemission systems.
Collapse
Affiliation(s)
- Xingjiang Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
| | | | | | | | | | | |
Collapse
|
37
|
Ligges M, Avigo I, Golež D, Strand HUR, Beyazit Y, Hanff K, Diekmann F, Stojchevska L, Kalläne M, Zhou P, Rossnagel K, Eckstein M, Werner P, Bovensiepen U. Ultrafast Doublon Dynamics in Photoexcited 1T-TaS_{2}. PHYSICAL REVIEW LETTERS 2018; 120:166401. [PMID: 29756943 DOI: 10.1103/physrevlett.120.166401] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 12/28/2017] [Indexed: 06/08/2023]
Abstract
Strongly correlated materials exhibit intriguing properties caused by intertwined microscopic interactions that are hard to disentangle in equilibrium. Employing nonequilibrium time-resolved photoemission spectroscopy on the quasi-two-dimensional transition-metal dichalcogenide 1T-TaS_{2}, we identify a spectroscopic signature of doubly occupied sites (doublons) that reflects fundamental Mott physics. Doublon-hole recombination is estimated to occur on timescales of electronic hopping ℏ/J≈14 fs. Despite strong electron-phonon coupling, the dynamics can be explained by purely electronic effects captured by the single-band Hubbard model under the assumption of weak hole doping, in agreement with our static sample characterization. This sensitive interplay of static doping and vicinity to the metal-insulator transition suggests a way to modify doublon relaxation on the few-femtosecond timescale.
Collapse
Affiliation(s)
- M Ligges
- Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany
| | - I Avigo
- Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany
| | - D Golež
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - H U R Strand
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Y Beyazit
- Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany
| | - K Hanff
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - F Diekmann
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - L Stojchevska
- Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany
| | - M Kalläne
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - P Zhou
- Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany
| | - K Rossnagel
- Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany
| | - M Eckstein
- Max Planck Research Department for Structural Dynamics, University of Hamburg-CFEL, 22761 Hamburg, Germany
| | - P Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - U Bovensiepen
- Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany
| |
Collapse
|
38
|
Werdehausen D, Takayama T, Höppner M, Albrecht G, Rost AW, Lu Y, Manske D, Takagi H, Kaiser S. Coherent order parameter oscillations in the ground state of the excitonic insulator Ta 2NiSe 5. SCIENCE ADVANCES 2018; 4:eaap8652. [PMID: 29740599 PMCID: PMC5938280 DOI: 10.1126/sciadv.aap8652] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 02/12/2018] [Indexed: 05/29/2023]
Abstract
The excitonic insulator is an intriguing electronic phase of condensed excitons. A prominent candidate is the small bandgap semiconductor Ta2NiSe5, in which excitons are believed to undergo a Bose-Einstein condensation-like transition. However, direct experimental evidence for the existence of a coherent condensate in this material is still missing. A direct fingerprint of such a state would be the observation of its collective modes, which are equivalent to the Higgs and Goldstone modes in superconductors. We report evidence for the existence of a coherent amplitude response in the excitonic insulator phase of Ta2NiSe5. Using nonlinear excitations with short laser pulses, we identify a phonon-coupled state of the condensate that can be understood as a novel amplitude mode. The condensate density contribution substantiates the picture of an electronically driven phase transition and characterizes the transient order parameter of the excitonic insulator as a function of temperature and excitation density.
Collapse
Affiliation(s)
- Daniel Werdehausen
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany
| | - Tomohiro Takayama
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
| | - Marc Höppner
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Gelon Albrecht
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany
| | - Andreas W. Rost
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
| | - Yangfan Lu
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Dirk Manske
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Hidenori Takagi
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Stefan Kaiser
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany
| |
Collapse
|
39
|
Ryan RA, Williams S, Martin AV, Dilanian RA, Darmanin C, Putkunz CT, Wood D, Streltsov VA, Jones MWM, Gaffney N, Hofmann F, Williams GJ, Boutet S, Messerschmidt M, Seibert MM, Curwood EK, Balaur E, Peele AG, Nugent KA, Quiney HM, Abbey B. Measurements of Long-range Electronic Correlations During Femtosecond Diffraction Experiments Performed on Nanocrystals of Buckminsterfullerene. J Vis Exp 2017:56296. [PMID: 28872125 PMCID: PMC5614354 DOI: 10.3791/56296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The precise details of the interaction of intense X-ray pulses with matter are a topic of intense interest to researchers attempting to interpret the results of femtosecond X-ray free electron laser (XFEL) experiments. An increasing number of experimental observations have shown that although nuclear motion can be negligible, given a short enough incident pulse duration, electronic motion cannot be ignored. The current and widely accepted models assume that although electrons undergo dynamics driven by interaction with the pulse, their motion could largely be considered 'random'. This would then allow the supposedly incoherent contribution from the electronic motion to be treated as a continuous background signal and thus ignored. The original aim of our experiment was to precisely measure the change in intensity of individual Bragg peaks, due to X-ray induced electronic damage in a model system, crystalline C60. Contrary to this expectation, we observed that at the highest X-ray intensities, the electron dynamics in C60 were in fact highly correlated, and over sufficiently long distances that the positions of the Bragg reflections are significantly altered. This paper describes in detail the methods and protocols used for these experiments, which were conducted both at the Linac Coherent Light Source (LCLS) and the Australian Synchrotron (AS) as well as the crystallographic approaches used to analyse the data.
Collapse
Affiliation(s)
- Rebecca A Ryan
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne
| | - Sophie Williams
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne
| | - Andrew V Martin
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne
| | - Ruben A Dilanian
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne
| | - Connie Darmanin
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University
| | - Corey T Putkunz
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne
| | - David Wood
- Department of Physics, Imperial College London
| | | | - Michael W M Jones
- Science and Engineering Faculty, Queensland University of Technology
| | | | - Felix Hofmann
- Department of Engineering Science, University of Oxford
| | | | - Sebastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory
| | | | - M Marvin Seibert
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University
| | - Evan K Curwood
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University
| | - Eugeniu Balaur
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University
| | - Andrew G Peele
- Science and Engineering Faculty, Queensland University of Technology
| | - Keith A Nugent
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University
| | - Harry M Quiney
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne;
| | - Brian Abbey
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University;
| |
Collapse
|
40
|
Zhao R, Wang Y, Deng D, Luo X, Lu WJ, Sun YP, Liu ZK, Chen LQ, Robinson J. Tuning Phase Transitions in 1T-TaS 2 via the Substrate. NANO LETTERS 2017; 17:3471-3477. [PMID: 28463560 DOI: 10.1021/acs.nanolett.7b00418] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Phase transitions in 2D materials can lead to massive changes in electronic properties that enable novel electronic devices. Tantalum disulfide (TaS2), specifically the "1T" phase (1T-TaS2), exhibits a phase transition based on the formation of commensurate charge density waves (CCDW) at 180 K. In this work, we investigate the impact of substrate choice on the phase transitions in ultrathin 1T-TaS2. Doping and charge transfer from the substrate has little impact on CDW phase transitions. On the contrary, we demonstrated that substrate surface roughness is a primary extrinsic factor in CCDW transition temperature and hysteresis, where higher roughness leads to smaller transition hysteresis. Such roughness can be simulated via surface texturing of SiO2/Si substrates, which controllably and reproducibly induces periodic strain in the 1T-TaS2 and thereby enables the potential for engineering CDW phase transitions.
Collapse
Affiliation(s)
| | | | | | | | | | - Yu-Ping Sun
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University , Nanjing 210093, People's Republic of China
| | | | | | | |
Collapse
|
41
|
Optically excited structural transition in atomic wires on surfaces at the quantum limit. Nature 2017; 544:207-211. [DOI: 10.1038/nature21432] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/27/2017] [Indexed: 01/10/2023]
|
42
|
Mankowsky R, Liu B, Rajasekaran S, Liu HY, Mou D, Zhou XJ, Merlin R, Först M, Cavalleri A. Dynamical Stability Limit for the Charge Density Wave in K_{0.3}MoO_{3}. PHYSICAL REVIEW LETTERS 2017; 118:116402. [PMID: 28368632 DOI: 10.1103/physrevlett.118.116402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Indexed: 06/07/2023]
Abstract
We study the response of the one-dimensional charge density wave in K_{0.3}MoO_{3} to different types of excitation with femtosecond optical pulses. We compare direct excitation of the lattice at midinfrared frequencies with injection of quasiparticles across the low energy charge density wave gap and with charge transfer excitation in the near infrared. For all three cases, we observe a fluence threshold above which the amplitude-mode oscillation frequency is softened and the mode becomes increasingly damped. We show that all the data can be collapsed onto a universal curve in which the melting of the charge density wave occurs abruptly at a critical lattice excursion. These data highlight the existence of a universal stability limit for a charge density wave, reminiscent of the Lindemann criterion for the melting of a crystal lattice.
Collapse
Affiliation(s)
- R Mankowsky
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
- University of Hamburg, 22761 Hamburg, Germany
| | - B Liu
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - S Rajasekaran
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - H Y Liu
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - D Mou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X J Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - R Merlin
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - M Först
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - A Cavalleri
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
- University of Hamburg, 22761 Hamburg, Germany
- Department of Physics, Oxford University, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom
| |
Collapse
|
43
|
Liu G, Debnath B, Pope TR, Salguero TT, Lake RK, Balandin AA. A charge-density-wave oscillator based on an integrated tantalum disulfide-boron nitride-graphene device operating at room temperature. NATURE NANOTECHNOLOGY 2016; 11:845-850. [PMID: 27376243 DOI: 10.1038/nnano.2016.108] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/18/2016] [Indexed: 06/06/2023]
Abstract
The charge-density-wave (CDW) phase is a macroscopic quantum state consisting of a periodic modulation of the electronic charge density accompanied by a periodic distortion of the atomic lattice in quasi-1D or layered 2D metallic crystals. Several layered transition metal dichalcogenides, including 1T-TaSe2, 1T-TaS2 and 1T-TiSe2 exhibit unusually high transition temperatures to different CDW symmetry-reducing phases. These transitions can be affected by the environmental conditions, film thickness and applied electric bias. However, device applications of these intriguing systems at room temperature or their integration with other 2D materials have not been explored. Here, we demonstrate room-temperature current switching driven by a voltage-controlled phase transition between CDW states in films of 1T-TaS2 less than 10 nm thick. We exploit the transition between the nearly commensurate and the incommensurate CDW phases, which has a transition temperature of 350 K and gives an abrupt change in current accompanied by hysteresis. An integrated graphene transistor provides a voltage-tunable, matched, low-resistance load enabling precise voltage control of the circuit. The 1T-TaS2 film is capped with hexagonal boron nitride to provide protection from oxidation. The integration of these three disparate 2D materials in a way that exploits the unique properties of each yields a simple, miniaturized, voltage-controlled oscillator suitable for a variety of practical applications.
Collapse
Affiliation(s)
- Guanxiong Liu
- Department of Electrical and Computer Engineering, Nano-Device Laboratory (NDL) and Phonon Optimized Engineered Materials (POEM) Center, University of California - Riverside, Riverside, California 92521, USA
| | - Bishwajit Debnath
- Department of Electrical and Computer Engineering, Laboratory for Terascale and Terahertz Electronics (LATTE), University of California - Riverside, Riverside, California 92521, USA
| | - Timothy R Pope
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Tina T Salguero
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Roger K Lake
- Department of Electrical and Computer Engineering, Laboratory for Terascale and Terahertz Electronics (LATTE), University of California - Riverside, Riverside, California 92521, USA
| | - Alexander A Balandin
- Department of Electrical and Computer Engineering, Nano-Device Laboratory (NDL) and Phonon Optimized Engineered Materials (POEM) Center, University of California - Riverside, Riverside, California 92521, USA
| |
Collapse
|
44
|
Rohde G, Hendel A, Stange A, Hanff K, Oloff LP, Yang LX, Rossnagel K, Bauer M. Time-resolved ARPES with sub-15 fs temporal and near Fourier-limited spectral resolution. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:103102. [PMID: 27802702 DOI: 10.1063/1.4963668] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
An experimental setup for time- and angle-resolved photoelectron spectroscopy with sub-15 fs temporal resolution is presented. A hollow-fiber compressor is used for the generation of 6.5 fs white light pump pulses, and a high-harmonic-generation source delivers 11 fs probe pulses at a photon energy of 22.1 eV. A value of 13 fs full width at half-maximum of the pump-probe cross correlation signal is determined by analyzing a photoemission intensity transient probing a near-infrared interband transition in 1T-TiSe2. Notably, the energy resolution of the setup conforms to typical values reported in conventional time-resolved photoemission studies using high harmonics, and an ultimate resolution of 170 meV is feasible.
Collapse
Affiliation(s)
- G Rohde
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - A Hendel
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - A Stange
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - K Hanff
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - L-P Oloff
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - L X Yang
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - K Rossnagel
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - M Bauer
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| |
Collapse
|
45
|
Abbey B, Dilanian RA, Darmanin C, Ryan RA, Putkunz CT, Martin AV, Wood D, Streltsov V, Jones MWM, Gaffney N, Hofmann F, Williams GJ, Boutet S, Messerschmidt M, Seibert MM, Williams S, Curwood E, Balaur E, Peele AG, Nugent KA, Quiney HM. X-ray laser-induced electron dynamics observed by femtosecond diffraction from nanocrystals of Buckminsterfullerene. SCIENCE ADVANCES 2016; 2:e1601186. [PMID: 27626076 PMCID: PMC5017826 DOI: 10.1126/sciadv.1601186] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
Abstract
X-ray free-electron lasers (XFELs) deliver x-ray pulses with a coherent flux that is approximately eight orders of magnitude greater than that available from a modern third-generation synchrotron source. The power density of an XFEL pulse may be so high that it can modify the electronic properties of a sample on a femtosecond time scale. Exploration of the interaction of intense coherent x-ray pulses and matter is both of intrinsic scientific interest and of critical importance to the interpretation of experiments that probe the structures of materials using high-brightness femtosecond XFEL pulses. We report observations of the diffraction of extremely intense 32-fs nanofocused x-ray pulses by a powder sample of crystalline C60. We find that the diffraction pattern at the highest available incident power significantly differs from the one obtained using either third-generation synchrotron sources or XFEL sources operating at low output power and does not correspond to the diffraction pattern expected from any known phase of crystalline C60. We interpret these data as evidence of a long-range, coherent dynamic electronic distortion that is driven by the interaction of the periodic array of C60 molecular targets with intense x-ray pulses of femtosecond duration.
Collapse
Affiliation(s)
- Brian Abbey
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Ruben A. Dilanian
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Connie Darmanin
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Rebecca A. Ryan
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Corey T. Putkunz
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Andrew V. Martin
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - David Wood
- Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Victor Streltsov
- Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Michael W. M. Jones
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Naylyn Gaffney
- Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Felix Hofmann
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Garth J. Williams
- Brookhaven National Laboratory, PO Box 5000, Upton, NY 11973–5000, USA
| | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Marc Messerschmidt
- BioXFEL Science and Technology Center, 700 Ellicott Street, Buffalo, NY 1420, USA
| | - M. Marvin Seibert
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-751 24 Uppsala, Sweden
| | - Sophie Williams
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Evan Curwood
- Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria 3084, Australia
| | - Eugeniu Balaur
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Andrew G. Peele
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Keith A. Nugent
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Harry M. Quiney
- ARC Centre of Excellence in Advanced Molecular Imaging, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| |
Collapse
|
46
|
Hatayama M, Ichimaru S, Ohcni T, Takahashi EJ, Midorikawa K, Oku S. Wide-range narrowband multilayer mirror for selecting a single-order harmonic in the photon energy range of 40-70 eV. OPTICS EXPRESS 2016; 24:14546-14551. [PMID: 27410607 DOI: 10.1364/oe.24.014546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An experimental demonstration of a wide-range narrowband multilayer mirror for selecting a single-order high-harmonic (HH) beam from multiple-order harmonics in the photon energy range between 40 eV and 70 eV was carried out. This extreme ultraviolet (XUV) mirror, based on a pair of Zr and Al0.7Si0.3 multilayers, has a reflectivity of 20-35% and contrast of more than 7 with respect to neighboring HHs at angles of incidence from 10 to 56.9 degrees, assuming HHs pumped at 1.55 eV. Thus, specific single-order harmonic beams can be arbitrarily selected from multiple-order harmonics in this photo energy range. In addition, the dispersion for input pulses of the order of 1 fs is negligible. This simple-to-align optical component is useful for the many various applications in physics, chemistry and biology that use ultrafast monochromatic HH beams.
Collapse
|
47
|
Ma L, Ye C, Yu Y, Lu XF, Niu X, Kim S, Feng D, Tománek D, Son YW, Chen XH, Zhang Y. A metallic mosaic phase and the origin of Mott-insulating state in 1T-TaS2. Nat Commun 2016; 7:10956. [PMID: 26961788 PMCID: PMC4792954 DOI: 10.1038/ncomms10956] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 02/04/2016] [Indexed: 11/20/2022] Open
Abstract
Electron–electron and electron–phonon interactions are two major driving forces that stabilize various charge-ordered phases of matter. In layered compound 1T-TaS2, the intricate interplay between the two generates a Mott-insulating ground state with a peculiar charge-density-wave (CDW) order. The delicate balance also makes it possible to use external perturbations to create and manipulate novel phases in this material. Here, we study a mosaic CDW phase induced by voltage pulses, and find that the new phase exhibits electronic structures entirely different from that of the original Mott ground state. The mosaic phase consists of nanometre-sized domains characterized by well-defined phase shifts of the CDW order parameter in the topmost layer, and by altered stacking relative to the layers underneath. We discover that the nature of the new phase is dictated by the stacking order, and our results shed fresh light on the origin of the Mott phase in 1T-TaS2. In correlated materials, new phases emerge when the balance between many-body interactions is perturbed. Here, Ma et al. induce a mosaic charge-density-wave phase out of Mott insulating state in layered 1T-TaS2 by voltage pulses, which reveals a dominating role of interlayer stacking order.
Collapse
Affiliation(s)
- Liguo Ma
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Cun Ye
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Yijun Yu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Xiu Fang Lu
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.,Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.,Key Laboratory of Strongly Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Xiaohai Niu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Sejoong Kim
- Korea Institute for Advanced Study, Hoegiro 85, Seoul 02455, Korea
| | - Donglai Feng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - David Tománek
- Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824, USA
| | - Young-Woo Son
- Korea Institute for Advanced Study, Hoegiro 85, Seoul 02455, Korea
| | - Xian Hui Chen
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.,Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.,Key Laboratory of Strongly Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Yuanbo Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| |
Collapse
|
48
|
Rettig L, Cortés R, Chu JH, Fisher IR, Schmitt F, Moore RG, Shen ZX, Kirchmann PS, Wolf M, Bovensiepen U. Persistent order due to transiently enhanced nesting in an electronically excited charge density wave. Nat Commun 2016; 7:10459. [PMID: 26804717 PMCID: PMC4737756 DOI: 10.1038/ncomms10459] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 12/14/2015] [Indexed: 12/02/2022] Open
Abstract
Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time- and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of the dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. Our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order. Whilst excited electronic states may exhibit unique non-equilibrium behavior, order is inhibited by fluctuations. Here, the authors use femtosecond photoemission spectroscopy to demonstrate transient stabilization of charge density wave order in rare earth tritellurides after near-infrared excitation.
Collapse
Affiliation(s)
- L Rettig
- Fakultät für Physik, Universität Duisburg-Essen, Lotharstr. 1, D-47057 Duisburg, Germany.,Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - R Cortés
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.,Abteilung Physikalische Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany
| | - J-H Chu
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Via Pueblo Mall, Stanford, California 94305, USA.,SLAC National Accelerator Laboratory, Stanford Institute for Material and Energy Sciences, Menlo Park, 94025 California, USA
| | - I R Fisher
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Via Pueblo Mall, Stanford, California 94305, USA.,SLAC National Accelerator Laboratory, Stanford Institute for Material and Energy Sciences, Menlo Park, 94025 California, USA
| | - F Schmitt
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Via Pueblo Mall, Stanford, California 94305, USA
| | - R G Moore
- SLAC National Accelerator Laboratory, Stanford Institute for Material and Energy Sciences, Menlo Park, 94025 California, USA
| | - Z-X Shen
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Via Pueblo Mall, Stanford, California 94305, USA.,SLAC National Accelerator Laboratory, Stanford Institute for Material and Energy Sciences, Menlo Park, 94025 California, USA
| | - P S Kirchmann
- SLAC National Accelerator Laboratory, Stanford Institute for Material and Energy Sciences, Menlo Park, 94025 California, USA
| | - M Wolf
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.,Abteilung Physikalische Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany
| | - U Bovensiepen
- Fakultät für Physik, Universität Duisburg-Essen, Lotharstr. 1, D-47057 Duisburg, Germany.,Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| |
Collapse
|
49
|
Grubišić Čabo A, Miwa JA, Grønborg SS, Riley JM, Johannsen JC, Cacho C, Alexander O, Chapman RT, Springate E, Grioni M, Lauritsen JV, King PDC, Hofmann P, Ulstrup S. Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS2. NANO LETTERS 2015; 15:5883-7. [PMID: 26315566 DOI: 10.1021/acs.nanolett.5b01967] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The dynamics of excited electrons and holes in single layer (SL) MoS2 have so far been difficult to disentangle from the excitons that dominate the optical response of this material. Here, we use time- and angle-resolved photoemission spectroscopy for a SL of MoS2 on a metallic substrate to directly measure the excited free carriers. This allows us to ascertain a direct quasiparticle band gap of 1.95 eV and determine an ultrafast (50 fs) extraction of excited free carriers via the metal in contact with the SL MoS2. This process is of key importance for optoelectronic applications that rely on separated free carriers rather than excitons.
Collapse
Affiliation(s)
- Antonija Grubišić Čabo
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University , 8000 Aarhus C, Denmark
| | - Jill A Miwa
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University , 8000 Aarhus C, Denmark
| | - Signe S Grønborg
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University , 8000 Aarhus C, Denmark
| | - Jonathon M Riley
- SUPA, School of Physics and Astronomy, University of St. Andrews , St. Andrews, Fife KY16 9SS, United Kingdom
| | - Jens C Johannsen
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
| | - Cephise Cacho
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, United Kingdom
| | - Oliver Alexander
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, United Kingdom
| | - Richard T Chapman
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, United Kingdom
| | - Emma Springate
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, United Kingdom
| | - Marco Grioni
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
| | - Jeppe V Lauritsen
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University , 8000 Aarhus C, Denmark
| | - Phil D C King
- SUPA, School of Physics and Astronomy, University of St. Andrews , St. Andrews, Fife KY16 9SS, United Kingdom
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University , 8000 Aarhus C, Denmark
| | - Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University , 8000 Aarhus C, Denmark
| |
Collapse
|
50
|
Dakovski GL, Durakiewicz T, Zhu JX, Riseborough PS, Gu G, Gilbertson SM, Taylor A, Rodriguez G. Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:054501. [PMID: 26798826 PMCID: PMC4711645 DOI: 10.1063/1.4933133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/01/2015] [Indexed: 05/30/2023]
Abstract
A hallmark in the cuprate family of high-temperature superconductors is the nodal-antinodal dichotomy. In this regard, angle-resolved photoemission spectroscopy (ARPES) has proven especially powerful, providing band structure information directly in energy-momentum space. Time-resolved ARPES (trARPES) holds great promise of adding ultrafast temporal information, in an attempt to identify different interaction channels in the time domain. Previous studies of the cuprates using trARPES were handicapped by the low probing energy, which significantly limits the accessible momentum space. Using 20.15 eV, 12 fs pulses, we show for the first time the evolution of quasiparticles in the antinodal region of Bi2Sr2CaCu2O8+δ and demonstrate that non-monotonic relaxation dynamics dominates above a certain fluence threshold. The dynamics is heavily influenced by transient modification of the electron-phonon interaction and phase space restrictions, in stark contrast to the monotonic relaxation in the nodal and off-nodal regions.
Collapse
Affiliation(s)
- Georgi L Dakovski
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, USA
| | - Tomasz Durakiewicz
- Condensed Matter and Magnet Science, Materials Physics and Applications Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, USA
| | - Jian-Xin Zhu
- Physics of Condensed Matter and Complex Systems, Theoretical Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, USA
| | - Peter S Riseborough
- Department of Physics, Temple University , Philadelphia, Pennsylvania 19122, USA
| | - Genda Gu
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory , Upton, New York 11973, USA
| | - Steve M Gilbertson
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, USA
| | - Antoinette Taylor
- Materials Physics and Applications, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, USA
| | - George Rodriguez
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, USA
| |
Collapse
|