1
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Sternbach AJ, Chae SH, Latini S, Rikhter AA, Shao Y, Li B, Rhodes D, Kim B, Schuck PJ, Xu X, Zhu XY, Averitt RD, Hone J, Fogler MM, Rubio A, Basov DN. Programmable hyperbolic polaritons in van der Waals semiconductors. Science 2021; 371:617-620. [PMID: 33542134 DOI: 10.1126/science.abe9163] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Collective electronic modes or lattice vibrations usually prohibit propagation of electromagnetic radiation through the bulk of common materials over a frequency range associated with these oscillations. However, this textbook tenet does not necessarily apply to layered crystals. Highly anisotropic materials often display nonintuitive optical properties and can permit propagation of subdiffractional waveguide modes, with hyperbolic dispersion, throughout their bulk. Here, we report on the observation of optically induced electronic hyperbolicity in the layered transition metal dichalcogenide tungsten diselenide (WSe2). We used photoexcitation to inject electron-hole pairs in WSe2 and then visualized, by transient nanoimaging, the hyperbolic rays that traveled along conical trajectories inside of the crystal. We establish here the signatures of programmable hyperbolic electrodynamics and assess the role of quantum transitions of excitons within the Rydberg series in the observed polaritonic response.
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Affiliation(s)
- A J Sternbach
- Department of Physics, Columbia University, New York, NY 10027, USA.
| | - S H Chae
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - S Latini
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - A A Rikhter
- Department of Physics, University of California-San Diego, La Jolla, CA 92093, USA
| | - Y Shao
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - B Li
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - D Rhodes
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - B Kim
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - P J Schuck
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - X Xu
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - X-Y Zhu
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - R D Averitt
- Department of Physics, University of California-San Diego, La Jolla, CA 92093, USA
| | - J Hone
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - M M Fogler
- Department of Physics, University of California-San Diego, La Jolla, CA 92093, USA
| | - A Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany.,Center for Computational Quantum Physics (CCQ), Flatiron Institute, New York, NY 10010, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY 10027, USA
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2
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Ron A, Chaudhary S, Zhang G, Ning H, Zoghlin E, Wilson SD, Averitt RD, Refael G, Hsieh D. Ultrafast Enhancement of Ferromagnetic Spin Exchange Induced by Ligand-to-Metal Charge Transfer. Phys Rev Lett 2020; 125:197203. [PMID: 33216570 DOI: 10.1103/physrevlett.125.197203] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 08/17/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
We theoretically predict and experimentally demonstrate a nonthermal pathway to optically enhance superexchange interaction energies in a material based on exciting ligand-to-metal charge-transfer transitions, which introduces lower-order virtual hopping contributions that are absent in the ground state. We demonstrate this effect in the layered ferromagnetic insulator CrSiTe_{3} by exciting Te-to-Cr charge-transfer transitions using ultrashort laser pulses and detecting coherent phonon oscillations that are impulsively generated by superexchange enhancement via magneto-elastic coupling. This mechanism kicks in below the temperature scale where short-range in-plane spin correlations begin to develop and disappears when the excitation energy is tuned away from the charge-transfer resonance, consistent with our predictions.
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Affiliation(s)
- A Ron
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv, 69978, Israel
| | - S Chaudhary
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - G Zhang
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | - H Ning
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - E Zoghlin
- Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - S D Wilson
- Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - R D Averitt
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | - G Refael
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - D Hsieh
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
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3
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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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4
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McLeod AS, Zhang J, Gu MQ, Jin F, Zhang G, Post KW, Zhao XG, Millis AJ, Wu WB, Rondinelli JM, Averitt RD, Basov DN. Multi-messenger nanoprobes of hidden magnetism in a strained manganite. Nat Mater 2020; 19:397-404. [PMID: 31844275 DOI: 10.1038/s41563-019-0533-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
The ground-state properties of correlated electron systems can be extraordinarily sensitive to external stimuli, offering abundant platforms for functional materials. Using the multi-messenger combination of atomic force microscopy, cryogenic scanning near-field optical microscopy, magnetic force microscopy and ultrafast laser excitation, we demonstrate both 'writing' and 'erasing' of a metastable ferromagnetic metal phase in strained films of La2/3Ca1/3MnO3 (LCMO) with nanometre-resolved finesse. By tracking both optical conductivity and magnetism at the nanoscale, we reveal how strain-coupling underlies the dynamic growth, spontaneous nanotexture and first-order melting transition of this hidden photoinduced metal. Our first-principles calculations reveal that epitaxially engineered Jahn-Teller distortion can stabilize nearly degenerate antiferromagnetic insulator and ferromagnetic metal phases. We propose a Ginzburg-Landau description to rationalize the co-active interplay of strain, lattice distortions and magnetism nano-resolved here in strained LCMO, thus guiding future functional engineering of epitaxial oxides into the regime of phase-programmable materials.
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Affiliation(s)
- A S McLeod
- Department of Physics, Columbia University, New York, NY, USA.
| | - Jingdi Zhang
- Department of Physics, University of California San Diego, La Jolla, CA, USA.
- Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
| | - M Q Gu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - F Jin
- Hefei National Laboratory for Physical Sciences at Microscale and High Magnetic Field Laboratory of CAS, University of Science and Technology of China, Hefei, China
| | - G Zhang
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - K W Post
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - X G Zhao
- Department of Mechanical Engineering, Boston University, Boston, MA, USA
| | - A J Millis
- Department of Physics, Columbia University, New York, NY, USA
| | - W B Wu
- Hefei National Laboratory for Physical Sciences at Microscale and High Magnetic Field Laboratory of CAS, University of Science and Technology of China, Hefei, China
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China
| | - J M Rondinelli
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - R D Averitt
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY, USA
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5
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Basov DN, Averitt RD, Hsieh D. Towards properties on demand in quantum materials. Nat Mater 2017; 16:1077-1088. [PMID: 29066824 DOI: 10.1038/nmat5017] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/22/2017] [Indexed: 05/21/2023]
Abstract
The past decade has witnessed an explosion in the field of quantum materials, headlined by the predictions and discoveries of novel Landau-symmetry-broken phases in correlated electron systems, topological phases in systems with strong spin-orbit coupling, and ultra-manipulable materials platforms based on two-dimensional van der Waals crystals. Discovering pathways to experimentally realize quantum phases of matter and exert control over their properties is a central goal of modern condensed-matter physics, which holds promise for a new generation of electronic/photonic devices with currently inaccessible and likely unimaginable functionalities. In this Review, we describe emerging strategies for selectively perturbing microscopic interaction parameters, which can be used to transform materials into a desired quantum state. Particular emphasis will be placed on recent successes to tailor electronic interaction parameters through the application of intense fields, impulsive electromagnetic stimulation, and nanostructuring or interface engineering. Together these approaches outline a potential roadmap to an era of quantum phenomena on demand.
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Affiliation(s)
- D N Basov
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - R D Averitt
- Department of Physics, University of California San Diego, La Jolla, California 92093, USA
| | - D Hsieh
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
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6
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Zhang J, Tan X, Liu M, Teitelbaum SW, Post KW, Jin F, Nelson KA, Basov DN, Wu W, Averitt RD. Cooperative photoinduced metastable phase control in strained manganite films. Nat Mater 2016; 15:956-960. [PMID: 27400387 DOI: 10.1038/nmat4695] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 06/10/2016] [Indexed: 06/06/2023]
Abstract
A major challenge in condensed-matter physics is active control of quantum phases. Dynamic control with pulsed electromagnetic fields can overcome energetic barriers, enabling access to transient or metastable states that are not thermally accessible. Here we demonstrate strain-engineered tuning of La2/3Ca1/3MnO3 into an emergent charge-ordered insulating phase with extreme photo-susceptibility, where even a single optical pulse can initiate a transition to a long-lived metastable hidden metallic phase. Comprehensive single-shot pulsed excitation measurements demonstrate that the transition is cooperative and ultrafast, requiring a critical absorbed photon density to activate local charge excitations that mediate magnetic-lattice coupling that, in turn, stabilize the metallic phase. These results reveal that strain engineering can tune emergent functionality towards proximal macroscopic states to enable dynamic ultrafast optical phase switching and control.
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Affiliation(s)
- Jingdi Zhang
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
- Department of Physics, Boston University, Boston, Massachusetts 02215, USA
| | - Xuelian Tan
- Hefei National Laboratory for Physical Sciences at Microscale, and High Magnetic Field Laboratory of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Mengkun Liu
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
- Department of Physics, Stony Brook University, Stony Brook, New York 11790, USA
| | - S W Teitelbaum
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - K W Post
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| | - Feng Jin
- Hefei National Laboratory for Physical Sciences at Microscale, and High Magnetic Field Laboratory of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - K A Nelson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - D N Basov
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| | - Wenbin Wu
- Hefei National Laboratory for Physical Sciences at Microscale, and High Magnetic Field Laboratory of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Advanced Microstructure, Nanjing 210093, China
| | - R D Averitt
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
- Department of Physics, Boston University, Boston, Massachusetts 02215, USA
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7
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Liu MK, Wagner M, Abreu E, Kittiwatanakul S, McLeod A, Fei Z, Goldflam M, Dai S, Fogler MM, Lu J, Wolf SA, Averitt RD, Basov DN. Anisotropic electronic state via spontaneous phase separation in strained vanadium dioxide films. Phys Rev Lett 2013; 111:096602. [PMID: 24033058 DOI: 10.1103/physrevlett.111.096602] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Indexed: 06/02/2023]
Abstract
We resolved the enigma of anisotropic electronic transport in strained vanadium dioxide (VO2) films by inquiring into the role that strain plays in the nanoscale phase separation in the vicinity of the insulator-to-metal transition. The root source of the anisotropy was visualized as the formation of a peculiar unidirectional stripe state which accompanies the phase transition. Furthermore, nanoscale infrared spectroscopy unveils distinct facets of electron-lattice interplay at three different stages of the phase transition. These stages include the initial formation of sparse nonpercolating metallic domains without noticeable involvement of the lattice followed by an electron-lattice coupled anisotropic stripe state close to percolation which ultimately evolves into a nearly isotropic rutile metallic phase. Our results provide a unique mesoscopic perspective for the tunable macroscopic phenomena in strained metal oxide films.
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Affiliation(s)
- M K Liu
- Department of Physics, The University of California at San Diego, La Jolla, California 92093, USA
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8
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Hwang HY, Liu M, Fan K, Zhang J, Strikwerda AC, Sternbach A, Brandt NC, Perkins BG, Zhang X, Averitt RD, Nelson KA. Metamaterial-Enhanced Nonlinear Terahertz Spectroscopy. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134109005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Liu MK, Pardo B, Zhang J, Qazilbash MM, Yun SJ, Fei Z, Shin JH, Kim HT, Basov DN, Averitt RD. Photoinduced phase transitions by time-resolved far-infrared spectroscopy in V2O3. Phys Rev Lett 2011; 107:066403. [PMID: 21902347 DOI: 10.1103/physrevlett.107.066403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 05/12/2011] [Indexed: 05/31/2023]
Abstract
Using time-resolved far-infrared spectroscopy, we observe multiple routes for photoinduced phase transitions in V(2)O(3). This includes (i) a photothermal antiferromagnetic to paramagnetic transition and (ii) an incipient strain-generated paramagnetic metal to paramagnetic insulator transition, which manifests as coherent oscillations in the far-infrared conductivity. The ∼100 ps conductivity oscillation results from coherent acoustic phonon modulation of the bandwidth W. Our results indicate that poor metals are particularly amenable to coherent strain control of their electronic properties.
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Affiliation(s)
- M K Liu
- Department of Physics, Boston University, Massachusetts 02215, USA
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10
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Tao H, Strikwerda AC, Fan K, Padilla WJ, Zhang X, Averitt RD. Reconfigurable terahertz metamaterials. Phys Rev Lett 2009; 103:147401. [PMID: 19905602 DOI: 10.1103/physrevlett.103.147401] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/10/2009] [Indexed: 05/13/2023]
Abstract
We demonstrate reconfigurable anisotropic metamaterials at terahertz frequencies where artificial "atoms" reorient within unit cells in response to an external stimulus. This is accomplished by fabricating planar arrays of split ring resonators on bimaterial cantilevers designed to bend out of plane in response to a thermal stimulus. We observe a marked tunability of the electric and magnetic response as the split ring resonators reorient within their unit cells. Our results demonstrate that adaptive metamaterials offer significant potential to realize novel electromagnetic functionality ranging from thermal detection to reconfigurable cloaks or absorbers.
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Affiliation(s)
- Hu Tao
- Department of Mechanical Engineering, Boston University, 110 Cummington Street, Boston, Massachusetts 02215, USA
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11
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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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12
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Talbayev D, LaForge AD, Trugman SA, Hur N, Taylor AJ, Averitt RD, Basov DN. Magnetic exchange interaction between rare-earth and Mn ions in multiferroic hexagonal manganites. Phys Rev Lett 2008; 101:247601. [PMID: 19113663 DOI: 10.1103/physrevlett.101.247601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Indexed: 05/27/2023]
Abstract
We report a study of magnetic dynamics in multiferroic hexagonal manganite HoMnO3 by far-infrared spectroscopy. The low-temperature magnetic excitation spectrum of HoMnO3 consists of magnetic-dipole transitions of Ho ions within the crystal-field split J = 8 manifold and of the triangular antiferromagnetic resonance of Mn ions. We determine the effective spin Hamiltonian for the Ho ion ground state. The magnetic-field splitting of the Mn antiferromagnetic resonance allows us to measure the magnetic exchange coupling between the rare-earth and Mn ions.
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Affiliation(s)
- D Talbayev
- Center for Integrated Nanotechnologies, MS K771, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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13
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Talbayev D, Trugman SA, Balatsky AV, Kimura T, Taylor AJ, Averitt RD. Detection of coherent magnons via ultrafast pump-probe reflectance spectroscopy in multiferroic Ba0.6Sr1.4Zn2Fe12O22. Phys Rev Lett 2008; 101:097603. [PMID: 18851660 DOI: 10.1103/physrevlett.101.097603] [Citation(s) in RCA: 3] [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: 09/29/2007] [Indexed: 05/26/2023]
Abstract
We report the detection of a magnetic resonance mode in multiferroic Ba0.6Sr1.4Zn2Fe12O22 using time-domain pump-probe reflectance spectroscopy. Magnetic sublattice precession is coherently excited via picosecond thermal modification of the exchange energy. Importantly, this precession is recorded as a change in reflectance caused by the dynamic magnetoelectric effect. Thus, transient reflectance provides a sensitive probe of magnetization dynamics in materials with strong magnetoelectric coupling, such as multiferroics, revealing new possibilities for application in spintronics and ultrafast manipulation of magnetic moments.
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Affiliation(s)
- D Talbayev
- Center for Integrated Nanotechnologies, MS K771, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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14
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Prasankumar RP, Attaluri RS, Averitt RD, Urayama J, Weisse-Bernstein N, Rotella P, Stintz AD, Krishna S, Taylor AJ. Ultrafast carrier dynamics in an InAs/InGaAs quantum dots-in-a-well heterostructure. Opt Express 2008; 16:1165-1173. [PMID: 18542190 DOI: 10.1364/oe.16.001165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ultrafast differential transmission spectroscopy is used to explore temperature-dependent carrier dynamics in an InAs/InGaAs quantum dots-in-a-well heterostructure. Electron-hole pairs are optically injected into the three dimensional GaAs barriers, after which we monitor carrier relaxation into the two dimensional InGaAs quantum wells and the zero dimensional InAs quantum dots by tuning the probe photon energy. We find that carrier capture and relaxation are dominated by Auger carrier-carrier scattering at low temperatures, with thermal emission playing an increasing role with temperature. Our experiments provide essential insight into carrier relaxation across multiple spatial dimensions.
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Affiliation(s)
- R P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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15
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Burch KS, Chia EEM, Talbayev D, Sales BC, Mandrus D, Taylor AJ, Averitt RD. Coupling between an optical phonon and the Kondo effect. Phys Rev Lett 2008; 100:026409. [PMID: 18232899 DOI: 10.1103/physrevlett.100.026409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Indexed: 05/25/2023]
Abstract
We explore the ultrafast optical response of Yb14MnSb11, providing further evidence that this compound is the first d-electron, ferromagnetic, underscreened Kondo lattice. These results also provide the first demonstration of coupling between an optical phonon mode and the Kondo effect.
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Affiliation(s)
- K S Burch
- Los Alamos National Laboratory, MS K771, MPA-CINT, Los Alamos, New Mexico 87545, USA.
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16
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Hilton DJ, Prasankumar RP, Fourmaux S, Cavalleri A, Brassard D, El Khakani MA, Kieffer JC, Taylor AJ, Averitt RD. Enhanced photosusceptibility near Tc for the light-induced insulator-to-metal phase transition in vanadium dioxide. Phys Rev Lett 2007; 99:226401. [PMID: 18233305 DOI: 10.1103/physrevlett.99.226401] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Indexed: 05/22/2023]
Abstract
We use optical-pump terahertz-probe spectroscopy to investigate the near-threshold behavior of the photoinduced insulator-to-metal (IM) transition in vanadium dioxide thin films. Upon approaching Tc a reduction in the fluence required to drive the IM transition is observed, consistent with a softening of the insulating state due to an increasing metallic volume fraction (below the percolation limit). This phase coexistence facilitates the growth of a homogeneous metallic conducting phase following superheating via photoexcitation. A simple dynamic model using Bruggeman effective medium theory describes the observed initial condition sensitivity.
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Affiliation(s)
- D J Hilton
- Center for Integrated Nanotechnologies, MS K771, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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17
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Chia EEM, Zhu JX, Talbayev D, Averitt RD, Taylor AJ, Oh KH, Jo IS, Lee SI. Observation of competing order in a high-Tc superconductor using femtosecond optical pulses. Phys Rev Lett 2007; 99:147008. [PMID: 17930711 DOI: 10.1103/physrevlett.99.147008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Indexed: 05/25/2023]
Abstract
We present studies of the photoexcited quasiparticle dynamics in Tl(2)Ba(2)Ca(2)Cu(3)O(y) (Tl-2223) using femtosecond optical techniques. Deep into the superconducting state (below 40 K), a dramatic change occurs in the temporal dynamics associated with photoexcited quasiparticles rejoining the condensate. This is suggestive of entry into a coexistence phase which, as our analysis reveals, opens a gap in the density of states (in addition to the superconducting gap), and furthermore, competes with superconductivity resulting in a depression of the superconducting gap.
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Affiliation(s)
- Elbert E M Chia
- MPA-CINT and T-11, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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18
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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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19
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Affiliation(s)
- N. J. Halas
- a Department of Electrical and Computer Engineering , The Rice Quantum Institute Rice Unaversity , P. O. Box 1892, Houston , TX , 77251 Phone:
| | - V. Papanyan
- a Department of Electrical and Computer Engineering , The Rice Quantum Institute Rice Unaversity , P. O. Box 1892, Houston , TX , 77251 Phone:
- b Institute for Physical Research of Armenian Academy of Sciences , Ashturak 2, 375410, Armenian Republic
| | - R. D. Averitt
- a Department of Electrical and Computer Engineering , The Rice Quantum Institute Rice Unaversity , P. O. Box 1892, Houston , TX , 77251 Phone:
| | - P. Pippenger
- a Department of Electrical and Computer Engineering , The Rice Quantum Institute Rice Unaversity , P. O. Box 1892, Houston , TX , 77251 Phone:
| | - R. A. Cheville
- a Department of Electrical and Computer Engineering , The Rice Quantum Institute Rice Unaversity , P. O. Box 1892, Houston , TX , 77251 Phone:
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20
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Yellampalle B, Averitt RD, Taylor AJ. Unambiguous chirp characterization using modified-spectrum auto-interferometric correlation and pulse spectrum. Opt Express 2006; 14:8890-8899. [PMID: 19529269 DOI: 10.1364/oe.14.008890] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Modified-spectrum auto-interferometric correlation (MOSAIC), derived from a conventional second order interferometric autocorrelation trace, is a sensitive and visual chirp diagnostic method for ultrashort laser pulses. We construct several pairs of example pulse shapes that have nearly identical MOSAIC traces and demonstrate that chirp ambiguity can result when the field amplitude or spectrum are not known, thus making MOSAIC a qualitative tool for chirped pulses. However, when the pulse spectrum is known, a unique chirp reconstruction is possible. With the help of a new reconstruction technique, we experimentally demonstrate complete pulse characterization using MOSAIC envelopes and the pulse spectrum.
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21
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Padilla WJ, Taylor AJ, Highstrete C, Lee M, Averitt RD. Dynamical electric and magnetic metamaterial response at terahertz frequencies. Phys Rev Lett 2006; 96:107401. [PMID: 16605787 DOI: 10.1103/physrevlett.96.107401] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Indexed: 05/08/2023]
Abstract
Utilizing terahertz time domain spectroscopy, we have characterized the electromagnetic response of a planar array of split ring resonators (SRRs) fabricated upon a high resistivity GaAs substrate. The measured frequency dependent magnetic and electric resonances are in excellent agreement with theory and simulation. For two polarizations, the SRRs yield a negative electric response (epsilon < 0). We demonstrate, for the first time, dynamical control of the electrical response of the SRRs through photoexcitation of free carriers in the substrate. An excited carrier density of approximately 4 x 10(16) cm(-3) is sufficient to short the gap of the SRRs, thereby turning off the electric resonance, demonstrating the potential of such structures as terahertz switches. Because of the universality of metamaterial response over many decades of frequency, these results have implications for other regions of the electromagnetic spectrum.
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Affiliation(s)
- W J Padilla
- Los Alamos National Laboratory, MS G756, MST-CINT, New Mexico 87545, USA.
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22
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Prasankumar RP, Okamura H, Imai H, Shimakawa Y, Kubo Y, Trugman SA, Taylor AJ, Averitt RD. Coupled charge-spin dynamics of the magnetoresistive pyrochlore TI2Mn2O7 probed using ultrafast midinfrared spectroscopy. Phys Rev Lett 2005; 95:267404. [PMID: 16486404 DOI: 10.1103/physrevlett.95.267404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 10/05/2005] [Indexed: 05/06/2023]
Abstract
Optical-pump midinfrared probe spectroscopy is used to investigate coupled charge-spin dynamics in the magnetoresistive pyrochlore TI(2)Mn(2)O(7). We find that the temporal persistence of the photoexcited carrier density is strongly influenced by spin disorder above and below the ferromagnetic Curie temperature. Our results are consistent with a picture whereby spin disorder leads to spatial segregation of the initially excited Tl 6s-O 2p electron-hole pairs, effectively reducing the probability for recombination. This further implies that colossal magnetoresistance in these materials may be driven primarily by Mn t(2g) spin disorder.
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23
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Hilton DJ, Averitt RD, Meserole CA, Fisher GL, Funk DJ, Thompson JD, Taylor AJ. Terahertz emission via ultrashort-pulse excitation of magnetic metal films. Opt Lett 2004; 29:1805-1807. [PMID: 15352376 DOI: 10.1364/ol.29.001805] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We observe terahertz emission by optical rectification of an intense 1.5-eV, 50-fs pulse in single-crystal iron thin films grown by molecular beam epitaxy. The azimuthal dependence of the emission indicates the presence of a magnetic nonlinearity and a nonmagnetic surface nonlinearity.
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Affiliation(s)
- D J Hilton
- MST-10, DX-2, and NMT-16, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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24
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Funk DJ, Calgaro F, Averitt RD, Asaki MLT, Taylor AJ. THz transmission spectroscopy and imaging: application to the energetic materials PBX 9501 and PBX 9502. Appl Spectrosc 2004; 58:428-31. [PMID: 17140492 DOI: 10.1366/000370204773580275] [Citation(s) in RCA: 7] [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] [Indexed: 05/12/2023]
Abstract
We report the measurement of the effective complex index of refraction near 1 THz for the Plastic-Bonded eXplosives PBX 9501 and PBX 9502. These plastic-bonded explosives consist of organic crystalline energetic materials, HMX and TATB, embedded in a binder matrix. We find that they are partially transparent at a few hundred GHz and we have applied a two-dimensional imaging technique for the detection of pre-fabricated defects in small samples.
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Affiliation(s)
- David J Funk
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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25
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Demsar J, Averitt RD, Taylor AJ. Nonequilibrium Superconductivity Probed by Time-Resolved Far-Infrared Conductivity Dynamics: Comparison Between MgB2and YBa2Cu3O7. ACTA ACUST UNITED AC 2004. [DOI: 10.1023/b:josc.0000011858.63802.26] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Demsar J, Averitt RD, Taylor AJ, Kabanov VV, Kang WN, Kim HJ, Choi EM, Lee SI. Pair-breaking and superconducting state recovery dynamics in MgB2. Phys Rev Lett 2003; 91:267002. [PMID: 14754080 DOI: 10.1103/physrevlett.91.267002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2003] [Indexed: 05/24/2023]
Abstract
We present studies of the photoexcited quasiparticle dynamics in MgB2 where, using femtosecond optical techniques, Cooper pair-breaking dynamics (PBD) have been temporally resolved for the first time. The PBD are strongly temperature and photoexcitation intensity dependent. Analysis of the PBD using the Rothwarf-Taylor equations suggests that the anomalous PBD arises from the fact that in MgB2 photoexcitation is initially followed by energy relaxation to high frequency phonons instead of, as commonly assumed, e-e thermalization. Furthermore, the bare quasiparticle recombination rate and the probability for pair breaking by phonons have been determined.
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Affiliation(s)
- J Demsar
- Los Alamos National Laboratory, MST-10, Los Alamos, New Mexico 87545, USA
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27
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Demsar J, Averitt RD, Ahn KH, Graf MJ, Trugman SA, Kabanov VV, Sarrao JL, Taylor AJ. Quasiparticle relaxation dynamics in heavy fermion compounds. Phys Rev Lett 2003; 91:027401. [PMID: 12906507 DOI: 10.1103/physrevlett.91.027401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2003] [Indexed: 05/24/2023]
Abstract
We present the first femtosecond studies of electron-phonon (e-ph) thermalization in heavy-fermion compounds. The e-ph thermalization time tau(ep) increases below the Kondo temperature by more than 2 orders of magnitude as T=0 K is approached. Analysis using the two-temperature model and numerical simulations based on Boltzmann's equations suggest that this anomalous slowing down of the e-ph thermalization derives from the large electronic specific heat and the suppression of scattering between heavy electrons and phonons.
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Affiliation(s)
- J Demsar
- Los Alamos National Laboratory, Mail Stop K764, Los Alamos, New Mexico 87545, USA
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28
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Etheridge HT, Averitt RD, Halas NJ, Weisman RB. C60 Triplet Lifetimes: Vibrational Energy Dependence from 0 to 80,000 cm-1. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100029a003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Westcott SL, Averitt RD, Wolfgang JA, Nordlander P, Halas NJ. Adsorbate-Induced Quenching of Hot Electrons in Gold Core−Shell Nanoparticles. J Phys Chem B 2001. [DOI: 10.1021/jp011213t] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. L. Westcott
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005
| | - R. D. Averitt
- MST-10, Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - J. A. Wolfgang
- Department of Physics, Rice University, Houston, Texas 77005
| | - P. Nordlander
- Department of Physics, Rice University, Houston, Texas 77005
| | - N. J. Halas
- Department of Electrical and Computer Engineering and Department of Chemistry, Rice University, Houston, Texas 77005
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30
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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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31
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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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32
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Affiliation(s)
- P. M. Pippenger
- ECE Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892; Institute for Physical Research, Armenian National Academy of Sciences, Ashtarak-2, 378410, Armenia; and Physics Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892
| | - R. D. Averitt
- ECE Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892; Institute for Physical Research, Armenian National Academy of Sciences, Ashtarak-2, 378410, Armenia; and Physics Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892
| | - V. O. Papanyan
- ECE Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892; Institute for Physical Research, Armenian National Academy of Sciences, Ashtarak-2, 378410, Armenia; and Physics Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892
| | - P. Nordlander
- ECE Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892; Institute for Physical Research, Armenian National Academy of Sciences, Ashtarak-2, 378410, Armenia; and Physics Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892
| | - N. J. Halas
- ECE Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892; Institute for Physical Research, Armenian National Academy of Sciences, Ashtarak-2, 378410, Armenia; and Physics Department and The Rice Quantum Institute, Rice University, Houston, Texas 77251−1892
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