1
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Laser-induced transient magnons in Sr 3Ir 2O 7 throughout the Brillouin zone. Proc Natl Acad Sci U S A 2021; 118:2103696118. [PMID: 34039712 DOI: 10.1073/pnas.2103696118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although ultrafast manipulation of magnetism holds great promise for new physical phenomena and applications, targeting specific states is held back by our limited understanding of how magnetic correlations evolve on ultrafast timescales. Using ultrafast resonant inelastic X-ray scattering we demonstrate that femtosecond laser pulses can excite transient magnons at large wavevectors in gapped antiferromagnets and that they persist for several picoseconds, which is opposite to what is observed in nearly gapless magnets. Our work suggests that materials with isotropic magnetic interactions are preferred to achieve rapid manipulation of magnetism.
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2
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Abreu E, Meyers D, Thorsmølle VK, Zhang J, Liu X, Geng K, Chakhalian J, Averitt RD. Nucleation and Growth Bottleneck in the Conductivity Recovery Dynamics of Nickelate Ultrathin Films. NANO LETTERS 2020; 20:7422-7428. [PMID: 32902285 DOI: 10.1021/acs.nanolett.0c02828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigate THz conductivity dynamics in NdNiO3 and EuNiO3 ultrathin films (15 unit cells, u.c., ∼5.7 nm thick) following a photoinduced thermal quench into the metallic state and reveal a clear contrast between first- and second-order dynamics. While in EuNiO3 the conductivity recovers exponentially, in NdNiO3 the recovery is nonexponential and slower than a simple thermal model. Crucially, it is consistent with first-order dynamics and well-described by a 2d Avrami model, with supercooling leading to metastable phase coexistence on the nano- to mesoscopic scale. This novel observation is a fundamentally dynamic manifestation of the first-order character of the insulator-to-metal transition, which the nanoscale thickness of our films and their fast cooling rate enable us to detect. The large transients seen in our films are promising for fast electronic (and magnetic) switching applications.
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Affiliation(s)
- E Abreu
- Institute for Quantum Electronics, Department of Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - D Meyers
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - V K Thorsmølle
- Department of Physics, Boston University, Boston, Massachusetts 02215, United States
- Department of Physics, UC San Diego, La Jolla, California 92093, United States
| | - J Zhang
- Department of Physics, UC San Diego, La Jolla, California 92093, United States
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - X Liu
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - K Geng
- Department of Physics, Boston University, Boston, Massachusetts 02215, United States
| | - J Chakhalian
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - R D Averitt
- Department of Physics, UC San Diego, La Jolla, California 92093, United States
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3
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Merritt AM, Christianson AD, Banerjee A, Gu GD, Mishchenko AS, Reznik D. Giant electron-phonon coupling of the breathing plane oxygen phonons in the dynamic stripe phase of [Formula: see text]. Sci Rep 2020; 10:11426. [PMID: 32651413 PMCID: PMC7351770 DOI: 10.1038/s41598-020-67963-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/19/2020] [Indexed: 11/08/2022] Open
Abstract
Doped antiferromagnets host a vast array of physical properties and learning how to control them is one of the biggest challenges of condensed matter physics. [Formula: see text] (LSNO) is a classic example of such a material. At low temperatures holes introduced via substitution of La by Sr segregate into lines to form boundaries between magnetically ordered domains in the form of stripes. The stripes become dynamic at high temperatures, but LSNO remains insulating presumably because an interplay between magnetic correlations and electron-phonon coupling localizes charge carriers. Magnetic degrees of freedom have been extensively investigated in this system, but phonons are almost completely unexplored. We searched for electron-phonon anomalies in LSNO by inelastic neutron scattering. Giant renormalization of plane Ni-O bond-stretching modes that modulate the volume around Ni appears on entering the dynamic charge stripe phase. Other phonons are a lot less sensitive to stripe melting. Dramatic overdamping of the breathing modes indicates that dynamic stripe phase may host small polarons. We argue that this feature sets electron-phonon coupling in nickelates apart from that in cuprates where breathing phonons are not overdamped and point out remarkable similarities with the colossal magnetoresistance manganites.
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Affiliation(s)
- A. M. Merritt
- Department of Physics, University of Colorado-Boulder, Boulder, CO 80309 USA
| | - A. D. Christianson
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - A. Banerjee
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - G. D. Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973 USA
| | - A. S. Mishchenko
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
- National Research Center “Kurchatov Institute”, 123182 Moscow, Russia
| | - D. Reznik
- Department of Physics, University of Colorado-Boulder, Boulder, CO 80309 USA
- Center for Experiments on Quantum Materials, University of Colorado-Boulder, Boulder, CO 80309 USA
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4
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Direct Visualization of Spatial Inhomogeneity of Spin Stripes Order in La1.72Sr0.28NiO4. CONDENSED MATTER 2019. [DOI: 10.3390/condmat4030077] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In several strongly correlated electron systems, the short range ordering of defects, charge and local lattice distortions are found to show complex inhomogeneous spatial distributions. There is growing evidence that such inhomogeneity plays a fundamental role in unique functionality of quantum complex materials. La1.72Sr0.28NiO4 is a prototypical strongly correlated perovskite showing spin stripes order. In this work we present the spatial distribution of the spin order inhomogeneity by applying micro X-ray diffraction to La1.72Sr0.28NiO4, mapping the spin-density-wave order below the 120 K onset temperature. We find that the spin-density-wave order shows the formation of nanoscale puddles with large spatial fluctuations. The nano-puddle density changes on the microscopic scale forming a multiscale phase separation extending from nanoscale to micron scale with scale-free distribution. Indeed spin-density-wave striped puddles are disconnected by spatial regions with negligible spin-density-wave order. The present work highlights the complex spatial nanoscale phase separation of spin stripes in nickelate perovskites and opens new perspectives of local spin order control by strain.
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5
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Sluchanko NE, Azarevich AN, Bogach AV, Bolotina NB, Glushkov VV, Demishev SV, Dudka AP, Khrykina ON, Filipov VB, Shitsevalova NY, Komandin GA, Muratov AV, Aleshchenko YA, Zhukova ES, Gorshunov BP. Observation of dynamic charge stripes in Tm 0.19Yb 0.81B 12 at the metal-insulator transition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:065604. [PMID: 30524111 DOI: 10.1088/1361-648x/aaf44e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Accurate low temperature charge transport measurements in combination with high-precision x-ray diffraction experiments have allowed detection of the symmetry lowering in the single domain Tm0.19Yb0.81B12 crystals that belong to the family of dodecaborides with metal-insulator transition. Based on the fine structure analysis we discover the formation of dynamic charge stripes within the semiconducting matrix of Tm0.19Yb0.81B12. The charge dynamics in these conducting nano-size channels is characterized by broad-band optical spectroscopy that allowed estimating the frequency (~2.4 × 1011 Hz) of quantum motion of the charge carriers. It is suggested that cooperative Jahn-Teller effect in the boron sublattice is a cause of the large-amplitude rattling modes of the Tm and Yb ions responsible for the 'modulation' of the conduction band along one of the [Formula: see text] directions through the variation of 5d-2p hybridization of electron states.
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Affiliation(s)
- N E Sluchanko
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov str. 38, Moscow 119991, Russia. Moscow Institute of Physics and Technology, 9, Institutskii per., Dolgoprudnyi, Moscow region 141700, Russia
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6
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Curtis JA, Burch AD, Barman B, Linn AG, McClintock LM, O'Beirne AL, Stiles MJ, Reno JL, McGill SA, Karaiskaj D, Hilton DJ. Broadband ultrafast terahertz spectroscopy in the 25 T Split Florida-Helix. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:073901. [PMID: 30068119 DOI: 10.1063/1.5023384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We describe the development of a broadband (0.3-10 THz) optical pump-terahertz probe spectrometer with an unprecedented combination of temporal resolution (≤200 fs) operating in external magnetic fields as high as 25 T using the new Split Florida-Helix magnet system. Using this new instrument, we measure the transient dynamics in a gallium arsenide four-quantum well sample after photoexcitation at 800 nm.
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Affiliation(s)
- Jeremy A Curtis
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Ashlyn D Burch
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Biplob Barman
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - A Garrison Linn
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Luke M McClintock
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Aidan L O'Beirne
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Matthew J Stiles
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - John L Reno
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Stephen A McGill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Denis Karaiskaj
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - David J Hilton
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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7
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Malvestuto M, Ciprian R, Caretta A, Casarin B, Parmigiani F. Ultrafast magnetodynamics with free-electron lasers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:053002. [PMID: 29315080 DOI: 10.1088/1361-648x/aaa211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The study of ultrafast magnetodynamics has entered a new era thanks to the groundbreaking technological advances in free-electron laser (FEL) light sources. The advent of these light sources has made possible unprecedented experimental schemes for time-resolved x-ray magneto-optic spectroscopies, which are now paving the road for exploring the ultimate limits of out-of-equilibrium magnetic phenomena. In particular, these studies will provide insights into elementary mechanisms governing spin and orbital dynamics, therefore contributing to the development of ultrafast devices for relevant magnetic technologies. This topical review focuses on recent advancement in the study of non-equilibrium magnetic phenomena from the perspective of time-resolved extreme ultra violet (EUV) and soft x-ray spectroscopies at FELs with highlights of some important experimental results.
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Affiliation(s)
- Marco Malvestuto
- Elettra-Sincrotrone Trieste S.C.p.A. Strada Statale 14-km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
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8
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Coslovich G, Kemper AF, Behl S, Huber B, Bechtel HA, Sasagawa T, Martin MC, Lanzara A, Kaindl RA. Ultrafast dynamics of vibrational symmetry breaking in a charge-ordered nickelate. SCIENCE ADVANCES 2017; 3:e1600735. [PMID: 29202025 PMCID: PMC5706742 DOI: 10.1126/sciadv.1600735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
The ability to probe symmetry-breaking transitions on their natural time scales is one of the key challenges in nonequilibrium physics. Stripe ordering represents an intriguing type of broken symmetry, where complex interactions result in atomic-scale lines of charge and spin density. Although phonon anomalies and periodic distortions attest the importance of electron-phonon coupling in the formation of stripe phases, a direct time-domain view of vibrational symmetry breaking is lacking. We report experiments that track the transient multi-terahertz response of the model stripe compound La1.75Sr0.25NiO4, yielding novel insight into its electronic and structural dynamics following an ultrafast optical quench. We find that although electronic carriers are immediately delocalized, the crystal symmetry remains initially frozen-as witnessed by time-delayed suppression of zone-folded Ni-O bending modes acting as a fingerprint of lattice symmetry. Longitudinal and transverse vibrations react with different speeds, indicating a strong directionality and an important role of polar interactions. The hidden complexity of electronic and structural coupling during stripe melting and formation, captured here within a single terahertz spectrum, opens new paths to understanding symmetry-breaking dynamics in solids.
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Affiliation(s)
- Giacomo Coslovich
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Alexander F. Kemper
- Computational Research Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Sascha Behl
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Bernhard Huber
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Hans A. Bechtel
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Takao Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - Michael C. Martin
- Advanced Light Source, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alessandra Lanzara
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Robert A. Kaindl
- Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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9
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Esposito V, Fechner M, Mankowsky R, Lemke H, Chollet M, Glownia JM, Nakamura M, Kawasaki M, Tokura Y, Staub U, Beaud P, Först M. Nonlinear Electron-Phonon Coupling in Doped Manganites. PHYSICAL REVIEW LETTERS 2017; 118:247601. [PMID: 28665638 DOI: 10.1103/physrevlett.118.247601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 05/19/2023]
Abstract
We employ time-resolved resonant x-ray diffraction to study the melting of charge order and the associated insulator-to-metal transition in the doped manganite Pr_{0.5}Ca_{0.5}MnO_{3} after resonant excitation of a high-frequency infrared-active lattice mode. We find that the charge order reduces promptly and highly nonlinearly as function of excitation fluence. Density-functional theory calculations suggest that direct anharmonic coupling between the excited lattice mode and the electronic structure drives these dynamics, highlighting a new avenue of nonlinear phonon control.
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Affiliation(s)
- V Esposito
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - M Fechner
- Max-Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
- Materials Theory, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - R Mankowsky
- Max-Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
- Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - H Lemke
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - M Chollet
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J M Glownia
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Nakamura
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - M Kawasaki
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - Y Tokura
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - M Först
- Max-Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
- Center for Free Electron Laser Science, 22761 Hamburg, Germany
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10
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Zhong R, Winn BL, Gu G, Reznik D, Tranquada JM. Evidence for a Nematic Phase in La_{1.75}Sr_{0.25}NiO_{4}. PHYSICAL REVIEW LETTERS 2017; 118:177601. [PMID: 28498689 DOI: 10.1103/physrevlett.118.177601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Indexed: 06/07/2023]
Abstract
Determining the nature of electronic states in doped Mott insulators remains a challenging task. In the case of tetragonal La_{2-x}Sr_{x}NiO_{4}, the occurrence of diagonal charge and spin stripe order in the ground state is now well established. In contrast, the nature of the high-temperature "disordered" state from which the stripe order develops has long been a subject of controversy, with considerable speculation regarding a polaronic liquid. Following the recent detection of dynamic charge stripes, we use neutron scattering measurements on an x=0.25 crystal to demonstrate that the dispersion of the charge-stripe excitations is anisotropic. This observation provides compelling evidence for the presence of electronic nematic order.
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Affiliation(s)
- Ruidan Zhong
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Materials Science and Engineering Department, Stony Brook University, Stony Brook, New York 11794, USA
| | - Barry L Winn
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Genda Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Dmitry Reznik
- Department of Physics, University of Colorado, Boulder, Colorado 80304, USA
| | - J M Tranquada
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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11
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Xu B, Dai YM, Zhao LX, Wang K, Yang R, Zhang W, Liu JY, Xiao H, Chen GF, Trugman SA, Zhu JX, Taylor AJ, Yarotski DA, Prasankumar RP, Qiu XG. Temperature-tunable Fano resonance induced by strong coupling between Weyl fermions and phonons in TaAs. Nat Commun 2017; 8:14933. [PMID: 28358027 PMCID: PMC5379101 DOI: 10.1038/ncomms14933] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/09/2017] [Indexed: 11/30/2022] Open
Abstract
Strong coupling between discrete phonon and continuous electron–hole pair excitations can induce a pronounced asymmetry in the phonon line shape, known as the Fano resonance. This effect has been observed in various systems. Here we reveal explicit evidence for strong coupling between an infrared-active phonon and electronic transitions near the Weyl points through the observation of a Fano resonance in the Weyl semimetal TaAs. The resulting asymmetry in the phonon line shape, conspicuous at low temperatures, diminishes continuously with increasing temperature. This behaviour originates from the suppression of electronic transitions near the Weyl points due to the decreasing occupation of electronic states below the Fermi level (EF) with increasing temperature, as well as Pauli blocking caused by thermally excited electrons above EF. Our findings not only elucidate the mechanism governing the tunable Fano resonance but also open a route for exploring exotic physical phenomena through phonon properties in Weyl semimetals. The study of lattice vibrations coupled to electronic excitations may provide an avenue for exploring exotic physical phenomena. Here, Xu et al. observe a Fano resonance in the Weyl semimetal TaAs, revealing evidence for a strong coupling between phonons and Weyl fermions.
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Affiliation(s)
- B Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.,Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
| | - Y M Dai
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L X Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
| | - K Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
| | - R Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
| | - W Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
| | - J Y Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
| | - H Xiao
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
| | - G F Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
| | - S A Trugman
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.,Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J-X Zhu
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.,Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A J Taylor
- Associate Directorate for Chemistry, Life and Earth Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - D A Yarotski
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - X G Qiu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
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12
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Wall S, Trigo M. Recent Developments in Ultrafast X-ray Techniques for Materials Science Applications. ACTA ACUST UNITED AC 2016. [DOI: 10.1080/08940886.2016.1220273] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Madan I, Kurosawa T, Toda Y, Oda M, Mertelj T, Mihailovic D. Evidence for carrier localization in the pseudogap state of cuprate superconductors from coherent quench experiments. Nat Commun 2015; 6:6958. [PMID: 25891310 PMCID: PMC4411302 DOI: 10.1038/ncomms7958] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 03/19/2015] [Indexed: 11/09/2022] Open
Abstract
A 'pseudogap' was introduced by Mott to describe a state of matter that has a minimum in the density of states at the Fermi level, deep enough for states to become localized. It can arise either from Coulomb repulsion between electrons, and/or incipient charge or spin order. Here we employ ultrafast spectroscopy to study dynamical properties of the normal to pseudogap state transition in the prototype high-temperature superconductor Bi2Sr2CaCu2O8+δ. We perform a systematic temperature and doping dependence study of the pseudogap photodestruction and recovery in coherent quench experiments, revealing marked absence of critical behaviour of the elementary excitations, which implies an absence of collective electronic ordering beyond a few coherence lengths on short timescales. The data imply ultrafast carrier localization into a textured polaronic state arising from a competing Coulomb interaction and lattice strain, enhanced by a Fermi surface instability.
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Affiliation(s)
- I Madan
- Jozef Stefan Institute and International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - T Kurosawa
- Department of Physics, Hokkaido University, Sapporo 060-0810, Japan
| | - Y Toda
- Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Japan
| | - M Oda
- Department of Physics, Hokkaido University, Sapporo 060-0810, Japan
| | - T Mertelj
- Jozef Stefan Institute and International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - D Mihailovic
- Jozef Stefan Institute and International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
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14
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Park BW, Jain SM, Zhang X, Hagfeldt A, Boschloo G, Edvinsson T. Resonance Raman and excitation energy dependent charge transfer mechanism in halide-substituted hybrid perovskite solar cells. ACS NANO 2015; 9:2088-101. [PMID: 25668059 DOI: 10.1021/nn507345e] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Organo-metal halide perovskites (OMHPs) are materials with attractive properties for optoelectronics. They made a recent introduction in the photovoltaics world by methylammonium (MA) lead triiodide and show remarkably improved charge separation capabilities when chloride and bromide are added. Here we show how halide substitution in OMHPs with the nominal composition CH3NH3PbI2X, where X is I, Br, or Cl, influences the morphology, charge quantum yield, and local interaction with the organic MA cation. X-ray diffraction and photoluminescence data demonstrate that halide substitution affects the local structure in the OMHPs with separate MAPbI3 and MAPbCl3 phases. Raman spectroscopies as well as theoretical vibration calculations reveal that this at the same time delocalizes the charge to the MA cation, which can liberate the vibrational movement of the MA cation, leading to a more adaptive organic phase. The resonance Raman effect together with quantum chemical calculations is utilized to analyze the change in charge transfer mechanism upon electronic excitation and gives important clues for the mechanism of the much improved photovoltage and photocurrent also seen in the solar cell performance for the materials when chloride compounds are included in the preparation.
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Affiliation(s)
- Byung-wook Park
- Department of Chemistry-Ångström Laboratory, Physical Chemistry, Uppsala University , Box 523, SE 751 20 Uppsala, Sweden
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Direct observation of dynamic charge stripes in La2-xSrxNiO4. Nat Commun 2014; 5:3467. [PMID: 24632780 DOI: 10.1038/ncomms4467] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/18/2014] [Indexed: 11/08/2022] Open
Abstract
The insulator-to-metal transition continues to be a challenging subject, especially when electronic correlations are strong. In layered compounds, such as La2-xSrxNiO4 and La2-xBaxCuO4, the doped charge carriers can segregate into periodically spaced charge stripes separating narrow domains of antiferromagnetic order. Although there have been theoretical proposals of dynamically fluctuating stripes, direct spectroscopic evidence of charge-stripe fluctuations has been lacking. Here we report the detection of critical lattice fluctuations, driven by charge-stripe correlations, in La2-xSrxNiO4 using inelastic neutron scattering. This scattering is detected at large momentum transfers where the magnetic form factor suppresses the spin fluctuation signal. The lattice fluctuations associated with the dynamic charge stripes are narrow in q and broad in energy. They are strongest near the charge-stripe melting temperature. Our results open the way towards the quantitative theory of dynamic stripes and for directly detecting dynamical charge stripes in other strongly correlated systems, including high-temperature superconductors such as La2-xSrxCuO4.
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