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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 Lett 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kung HH, Baumbach RE, Bauer ED, Thorsmølle VK, Zhang WL, Haule K, Mydosh JA, Blumberg G. Chirality density wave of the “hidden order” phase in URu
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Si
2. Science 2015; 347:1339-42. [DOI: 10.1126/science.1259729] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- H.-H. Kung
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - R. E. Baumbach
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - E. D. Bauer
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - V. K. Thorsmølle
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - W.-L. Zhang
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - K. Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - J. A. Mydosh
- Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden, Netherlands
| | - G. Blumberg
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
- National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
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Thorsmølle VK, Homes CC, Gozar A, Blumberg G, van Mechelen JLM, Kuzmenko AB, Vanishri S, Marin C, Rønnow HM. Phonon energy gaps in the charged incommensurate planes of the spin-ladder Sr14Cu24O41 compound by Raman and infrared spectroscopy. Phys Rev Lett 2012; 108:217401. [PMID: 23003300 DOI: 10.1103/physrevlett.108.217401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Indexed: 06/01/2023]
Abstract
The terahertz (THz) excitations in the quantum spin-ladder system Sr14Cu24O41 have been determined along the c axis using THz time-domain, Raman, and infrared spectroscopy. Low-frequency infrared and Raman active modes are observed above and below the charge-ordering temperature T(co) is approximately equal to 200 K over a narrow interval approximately equal to 1-2 meV approximately equal to 8-16 cm(-1)). A new infrared mode at approximately equal to 1 meV develops below approximately equal to 100 K. The temperature dependence of these modes shows that they are coupled to the charge- and spin-density-wave correlations in this system. These low-energy features are conjectured to originate in the gapped sliding motion of the chain and ladder subsystems, which are both incommensurate and charged.
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Affiliation(s)
- V K Thorsmølle
- Laboratory for Photonics and Interfaces, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Thorsmølle VK, Armitage NP. Ultrafast (but many-body) relaxation in a low-density electron glass. Phys Rev Lett 2010; 105:086601. [PMID: 20868121 DOI: 10.1103/physrevlett.105.086601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Indexed: 05/29/2023]
Abstract
We present a study of the relaxation dynamics of the photoexcited conductivity of the impurity states in the low-density electronic glass, phosphorous-doped silicon Si:P. Using subband gap optical pump-terahertz probe spectroscopy we find strongly temperature- and fluence-dependent glassy power-law relaxation occurring over subnanosecond time scales. Such behavior is in contrast to the much longer time scales found in higher electron density glassy systems. We also find evidence for both multiparticle relaxation mechanisms and/or coupling to electronic collective modes and a low temperature quantum relaxational regime.
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Affiliation(s)
- V K Thorsmølle
- Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Thorsmølle VK, Averitt RD, Demsar J, Smith DL, Tretiak S, Martin RL, Chi X, Crone BK, Ramirez AP, Taylor AJ. Morphology effectively controls singlet-triplet exciton relaxation and charge transport in organic semiconductors. Phys Rev Lett 2009; 102:017401. [PMID: 19257238 DOI: 10.1103/physrevlett.102.017401] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Indexed: 05/24/2023]
Abstract
We present a comparative study of ultrafast photoconversion dynamics in tetracene (Tc) and pentacene (Pc) single crystals and Pc films using optical pump-probe spectroscopy. Photoinduced absorption in Tc and Pc crystals is activated and temperature-independent, respectively, demonstrating dominant singlet-triplet exciton fission. In Pc films (as well as C60-doped films) this decay channel is suppressed by electron trapping. These results demonstrate the central role of crystallinity and purity in photogeneration processes and will constrain the design of future photovoltaic devices.
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Affiliation(s)
- V K Thorsmølle
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Thorsmølle VK, Averitt RD, Shibauchi T, Hundley MF, Taylor AJ. Dynamic coupling-decoupling crossover in the current-driven vortex state in Tl2Ba2CaCu2O8 probed by the Josephson plasma resonance. Phys Rev Lett 2006; 97:237001. [PMID: 17280231 DOI: 10.1103/physrevlett.97.237001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Indexed: 05/13/2023]
Abstract
We have used terahertz spectroscopy to measure the Josephson plasma resonance in the superconductor Tl2Ba2CaCu2O8+delta. This allows us to probe the longitudinal ordering of pancake vortices as a function of applied ab-plane current in a 2.5 kG c-axis magnetic field. With increasing current in the low temperature vortex solid phase, we observe a decrease in the interlayer phase coherence consistent with a progressive misalignment of the pancake vortices in neighboring layers. In the high temperature vortex liquid phase, an increase in the longitudinal ordering occurs above a certain threshold current. Our results show evidence of a current-driven coupling-decoupling crossover in the pinned liquid phase.
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Affiliation(s)
- V K Thorsmølle
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Thorsmølle VK, Averitt RD, Maley MP, Bulaevskii LN, Helm C, Taylor AJ. C-axis Josephson plasma resonance observed in Tl(2)Ba(2)CaCu(2)O(8) superconducting thin films by use of terahertz time-domain spectroscopy. Opt Lett 2001; 26:1292-1294. [PMID: 18049590 DOI: 10.1364/ol.26.001292] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have unambiguously observed the c -axis Josephson plasma resonance (JPR) in high-critical-temperature (T(c)) cuprate (Tl(2)Ba(2)CaCu(2)O(8)) superconducting thin films, employing terahertz time-domain spectroscopy in transmission as a function of temperature in zero magnetic field. These are believed to be the first measurements of the JPR temperature dependence of a high-T(c) material in transmission. With increasing temperature, the JPR shifts from 705 GHz at 10 K to ~170 GHz at 98 K, corresponding to an increase in c-axis penetration depth from 22.4+/-0.6mum to 94+/-9mum . The linewidth of the JPR peak increases with temperature, which indicates an increase in the quasi-particle scattering rate. We have probed the onset of the c -axis phase coherence to ~0.95T(c) . The JPR vanishes above T(c) as expected.
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Averitt RD, Lobad AI, Kwon C, Trugman SA, Thorsmølle VK, Taylor AJ. Ultrafast conductivity dynamics in colossal magnetoresistance manganites. Phys Rev Lett 2001; 87:017401. [PMID: 11461494 DOI: 10.1103/physrevlett.87.017401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2000] [Indexed: 05/22/2023]
Abstract
Ultrafast picosecond measurements of optically induced changes in the absolute conductivity (0.4-1.0 THz) of La0.7M0.3MnO3 thin films ( M = Ca, Sr) from 10 K to approximately 0.9 Tc reveal a two-component relaxation. A fast, approximately 2 ps, conductivity decrease arises from an optically induced modification of the effective phonon temperature. The slower component, related to spin-lattice relaxation, has a lifetime that increases upon approaching Tc from below in accordance with an increasing spin specific heat. We show that, for T<<Tc, partial differential sigma/ partial differential T is primarily determined by thermally disordered phonons while spin fluctuations dominate near Tc.
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Affiliation(s)
- R D Averitt
- Los Alamos National Lab, MS K764, Los Alamos, New Mexico 87545, USA.
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