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Macis S, Mosesso L, D'Arco A, Perucchi A, Di Pietro P, Lupi S. Anisotropic Optical Response of Ti-Doped VO 2 Single Crystals. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3121. [PMID: 38998204 PMCID: PMC11242553 DOI: 10.3390/ma17133121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/17/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024]
Abstract
This study delves into the effects of titanium (Ti) doping on the optical properties of vanadium dioxide (VO2), a material well known for its metal-to-insulator transition (MIT) near room temperature. By incorporating Ti into VO2's crystal lattice, we aim to uncover the resultant changes in its physical properties, crucial for enhancing its application in smart devices. Utilizing polarized infrared micro-spectroscopy, we examined TixV1-xO2 single crystals with varying Ti concentrations (x = 0.059, x = 0.082, and x = 0.187) across different crystal phases (the conductive rutile phase and insulating monoclinic phases M1 and M2) from the far-infrared to the visible spectral range. Our findings reveal that Ti doping significantly influences the phononic spectra, introducing absorption peaks not attributed to pure VO2 or TiO2. This is especially notable with polarization along the crystal growth axis, mainly in the x = 0.187 sample. Furthermore, we demonstrate that the electronic contribution to optical conductivity in the metallic phase exhibits strong anisotropy, higher along the c axis than the a-b plane. This anisotropy, coupled with the progressive broadening of the zone center infrared active phonon modes with increasing doping, highlights the complex interplay between structural and electronic dynamics in doped VO2. Our results underscore the potential of Ti doping in fine-tuning VO2's electronic and thermochromic properties, paving the way for its enhanced application in optoelectronic devices and technologies.
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Affiliation(s)
- Salvatore Macis
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Lorenzo Mosesso
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Annalisa D'Arco
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Andrea Perucchi
- Elettra-Sincrotrone Trieste S.C.p.A, S.S. 14 km163.5 in AREA Science Park, 34012 Trieste, Italy
| | - Paola Di Pietro
- Elettra-Sincrotrone Trieste S.C.p.A, S.S. 14 km163.5 in AREA Science Park, 34012 Trieste, Italy
| | - Stefano Lupi
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Elettra-Sincrotrone Trieste S.C.p.A, S.S. 14 km163.5 in AREA Science Park, 34012 Trieste, Italy
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2
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Yang Z, Jin KJ, Gan Y, Ma C, Zhong Z, Yuan Y, Ge C, Guo EJ, Wang C, Xu X, He M, Zhang D, Yang G. Photoinduced Phase Transition in Infinite-Layer Nickelates. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2304146. [PMID: 37356048 DOI: 10.1002/smll.202304146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/15/2023] [Indexed: 06/27/2023]
Abstract
The quantum phase transition caused by regulating the electronic correlation in strongly correlated quantum materials has been a research hotspot in condensed matter science. Herein, a photon-induced quantum phase transition from the Kondo-Mott insulating state to the low temperature metallic one accompanying with the magnetoresistance changing from negative to positive in the infinite-layer NdNiO2 films is reported, where the antiferromagnetic coupling among the Ni1+ localized spins and the Kondo effect are effectively suppressed by manipulating the correlation of Ni-3d and Nd-5d electrons under the photoirradiation. Moreover, the critical temperature Tc of the superconducting-like transition exhibits a dome-shaped evolution with the maximum up to ≈42 K, and the electrons dominate the transport process proved by the Hall effect measurements. These findings not only make the photoinduction a promising way to control the quantum phase transition by manipulating the electronic correlation in Mott-like insulators, but also shed some light on the possibility of the superconducting in electron-doped nickelates.
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Affiliation(s)
- Zhen Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Kui-Juan Jin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Yulin Gan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Cheng Ma
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo, 315201, China
| | - Ye Yuan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Chen Ge
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Er-Jia Guo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Can Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xiulai Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Meng He
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Dongxiang Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Guozhen Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
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3
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Han JE, Aron C, Chen X, Mansaray I, Han JH, Kim KS, Randle M, Bird JP. Correlated insulator collapse due to quantum avalanche via in-gap ladder states. Nat Commun 2023; 14:2936. [PMID: 37217490 DOI: 10.1038/s41467-023-38557-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
The significant discrepancy observed between the predicted and experimental switching fields in correlated insulators under a DC electric field far-from-equilibrium necessitates a reevaluation of current microscopic understanding. Here we show that an electron avalanche can occur in the bulk limit of such insulators at arbitrarily small electric field by introducing a generic model of electrons coupled to an inelastic medium of phonons. The quantum avalanche arises by the generation of a ladder of in-gap states, created by a multi-phonon emission process. Hot-phonons in the avalanche trigger a premature and partial collapse of the correlated gap. The phonon spectrum dictates the existence of two-stage versus single-stage switching events which we associate with charge-density-wave and Mott resistive phase transitions, respectively. The behavior of electron and phonon temperatures, as well as the temperature dependence of the threshold fields, demonstrates how a crossover between the thermal and quantum switching scenarios emerges within a unified framework of the quantum avalanche.
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Affiliation(s)
- Jong E Han
- Department of Physics, State University of New York at Buffalo, Buffalo, NY, 14260, USA.
| | - Camille Aron
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005, Paris, France
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Xi Chen
- Department of Physics, State University of New York at Buffalo, Buffalo, NY, 14260, USA
| | - Ishiaka Mansaray
- Department of Physics, State University of New York at Buffalo, Buffalo, NY, 14260, USA
| | - Jae-Ho Han
- Center for Theoretical Physics of Complex Systems, Institute for Basic Science(IBS), Daejeon, 34126, South Korea
| | - Ki-Seok Kim
- Department of Physics, POSTECH, Pohang, Gyeongbuk, 37673, South Korea
| | - Michael Randle
- Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY, 14260, USA
| | - Jonathan P Bird
- Department of Physics, State University of New York at Buffalo, Buffalo, NY, 14260, USA
- Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY, 14260, USA
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Liu R, Si L, Niu W, Zhang X, Chen Z, Zhu C, Zhuang W, Chen Y, Zhou L, Zhang C, Wang P, Song F, Tang L, Xu Y, Zhong Z, Zhang R, Wang X. Light-Induced Mott-Insulator-to-Metal Phase Transition in Ultrathin Intermediate-Spin Ferromagnetic Perovskite Ruthenates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211612. [PMID: 36626850 DOI: 10.1002/adma.202211612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Light control of emergent quantum phenomena is a widely used external stimulus for quantum materials. Generally, perovskite strontium ruthenate SrRuO3 has an itinerant ferromagnetism with a low-spin state. However, the phase of intermediate-spin (IS) ferromagnetic metallic state has never been seen. Here, by means of UV-light irradiation, a photocarrier-doping-induced Mott-insulator-to-metal phase transition is shown in a few atomic layers of perovskite IS ferromagnetic SrRuO3- δ . This new metastable IS metallic phase can be reversibly regulated due to the convenient photocharge transfer from SrTiO3 substrates to SrRuO3- δ ultrathin films. These dynamical mean-field theory calculations further verify such photoinduced electronic phase transformation, owing to oxygen vacancies and orbital reconstruction. The optical manipulation of charge-transfer finesse is an alternative pathway toward discovering novel metastable phases in strongly correlated systems and facilitates potential light-controlled device applications in optoelectronics and spintronics.
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Affiliation(s)
- Ruxin Liu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Liang Si
- School of Physics, Northwest University, Xi'an, 710127, China
- Institute of Solid State Physics, Vienna University of Technology, Vienna, 1040, Austria
| | - Wei Niu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Xu Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zhongqiang Chen
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Changzheng Zhu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Wenzhuo Zhuang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yongda Chen
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Liqi Zhou
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
| | - Chunchen Zhang
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
| | - Peng Wang
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Fengqi Song
- School of Physics, Nanjing University, Nanjing, 210093, China
| | - Lin Tang
- Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Yongbing Xu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo, 315201, China
| | - Rong Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Department of Physics, Xiamen University, Xiamen, 316005, China
| | - Xuefeng Wang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
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Nanoscale self-organization and metastable non-thermal metallicity in Mott insulators. Nat Commun 2022; 13:3730. [PMID: 35764628 PMCID: PMC9240065 DOI: 10.1038/s41467-022-31298-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 06/10/2022] [Indexed: 11/08/2022] Open
Abstract
Mott transitions in real materials are first order and almost always associated with lattice distortions, both features promoting the emergence of nanotextured phases. This nanoscale self-organization creates spatially inhomogeneous regions, which can host and protect transient non-thermal electronic and lattice states triggered by light excitation. Here, we combine time-resolved X-ray microscopy with a Landau-Ginzburg functional approach for calculating the strain and electronic real-space configurations. We investigate V2O3, the archetypal Mott insulator in which nanoscale self-organization already exists in the low-temperature monoclinic phase and strongly affects the transition towards the high-temperature corundum metallic phase. Our joint experimental-theoretical approach uncovers a remarkable out-of-equilibrium phenomenon: the photo-induced stabilisation of the long sought monoclinic metal phase, which is absent at equilibrium and in homogeneous materials, but emerges as a metastable state solely when light excitation is combined with the underlying nanotexture of the monoclinic lattice.
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Li X, Ning H, Mehio O, Zhao H, Lee MC, Kim K, Nakamura F, Maeno Y, Cao G, Hsieh D. Keldysh Space Control of Charge Dynamics in a Strongly Driven Mott Insulator. PHYSICAL REVIEW LETTERS 2022; 128:187402. [PMID: 35594087 DOI: 10.1103/physrevlett.128.187402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 02/20/2022] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
The fate of a Mott insulator under strong low frequency optical driving conditions is a fundamental problem in quantum many-body dynamics. Using ultrafast broadband optical spectroscopy, we measured the transient electronic structure and charge dynamics of an off-resonantly pumped Mott insulator Ca_{2}RuO_{4}. We observe coherent bandwidth renormalization and nonlinear doublon-holon pair production occurring in rapid succession within a sub-100-fs pump pulse duration. By sweeping the electric field amplitude, we demonstrate continuous bandwidth tuning and a Keldysh crossover from a multiphoton absorption to quantum tunneling dominated pair production regime. Our results provide a procedure to control coherent and nonlinear heating processes in Mott insulators, facilitating the discovery of novel out-of-equilibrium phenomena in strongly correlated systems.
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Affiliation(s)
- Xinwei Li
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - Honglie Ning
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - Omar Mehio
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - Hengdi Zhao
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Min-Cheol Lee
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Republic of Korea
| | - Kyungwan Kim
- Department of Physics, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Fumihiko Nakamura
- Department of Education and Creation Engineering, Kurume Institute of Technology, Fukuoka 830-0052, Japan
| | - Yoshiteru Maeno
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Gang Cao
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - David Hsieh
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
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Abstract
Advances over the past decade have presented new avenues to achieve control over material properties using intense pulses of electromagnetic radiation, with frequencies ranging from optical (approximately 1 PHz, or 1015 Hz) down to below 1 THz (1012 Hz). Some of these new developments have arisen from new experimental methods to drive and observe transient material properties, while others have emerged from new computational techniques that have made nonequilibrium dynamics more tractable to our understanding. One common issue with most attempts to realize control using electromagnetic pulses is the dissipation of energy, which in many cases poses a limit due to uncontrolled heating and has led to strong interest in using lower frequency and/or highly specific excitations to minimize this effect. Emergent developments in experimental tools using shaped X-ray pulses may in the future offer new possibilities for material control, provided that the issue of heat dissipation can be resolved for higher frequency light. The concept of using appropriately shaped pulses of light to control the properties of materials has a range of potential applications, and relies on an understanding of intricate couplings within the material.![]()
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Affiliation(s)
- Steven L Johnson
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
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Huitric G, Rodriguez-Fano M, Gournay L, Godin N, Herve M, Privault G, Tranchant J, Khaldi Z, Cammarata M, Collet E, Janod E, ODIN C. Impact of the TeraHertz and Optical pump penetration depths on generated strain waves temporal profiles in a V2O3 thin film. Faraday Discuss 2022; 237:389-405. [DOI: 10.1039/d2fd00013j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Triggering new stable macroscopic orders in materials by ultrafast optical or terahertz pump pulses is a difficult challenge, complicated by the interplay of multiscale microscopic mechanisms, and macroscopic excitation profiles...
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Broadband Anisotropic Optical Properties of the Terahertz Generator HMQ-TMS Organic Crystal. CONDENSED MATTER 2020. [DOI: 10.3390/condmat5030047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
HMQ-TMS (2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium 2,4,6-trimethylbenzenesulfonate) is a recently discovered anisotropic organic crystal that can be exploited for the production of broadband high-intensity terahertz (THz) radiation through the optical rectification (OR) technique. HMQ-TMS plays a central role in THz technology due to its broad transparency range, large electro-optic coefficient and coherence length, and excellent crystal properties. However, its anisotropic optical properties have not been deeply researched yet. Here, from polarized reflectance and transmittance measurements along the x 1 and x 3 axes of a HMQ-TMS single-crystal, we extract both the refraction index n and the extinction coefficient k between 50 and 35,000 cm − 1 . We further measure the THz radiation generated by optical rectification at different infrared (IR) wavelengths and along the two x 1 and x 3 axes. These data highlight the remarkable anisotropic linear and nonlinear optical behavior of HMQ-TMS crystals, expanding the knowledge of its properties and applications from the THz to the UV region.
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10
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Non-thermal resistive switching in Mott insulator nanowires. Nat Commun 2020; 11:2985. [PMID: 32532988 PMCID: PMC7293290 DOI: 10.1038/s41467-020-16752-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/20/2020] [Indexed: 11/26/2022] Open
Abstract
Resistive switching can be achieved in a Mott insulator by applying current/voltage, which triggers an insulator-metal transition (IMT). This phenomenon is key for understanding IMT physics and developing novel memory elements and brain-inspired technology. Despite this, the roles of electric field and Joule heating in the switching process remain controversial. Using nanowires of two archetypal Mott insulators—VO2 and V2O3 we unequivocally show that a purely non-thermal electrical IMT can occur in both materials. The mechanism behind this effect is identified as field-assisted carrier generation leading to a doping driven IMT. This effect can be controlled by similar means in both VO2 and V2O3, suggesting that the proposed mechanism is generally applicable to Mott insulators. The energy consumption associated with the non-thermal IMT is extremely low, rivaling that of state-of-the-art electronics and biological neurons. These findings pave the way towards highly energy-efficient applications of Mott insulators. Despite intensive research on the electrically driven insulator-to-metal transition, this phenomenon is not well understood. Using quasi 1D nanowires of two Mott insulators, the authors reveal the central role of defects in enabling a non-thermal doping driven insulator-to metal transition.
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Giorgianni F, Puc U, Jazbinsek M, Cea T, Koo MJ, Han JH, Kwon OP, Vicario C. Supercontinuum generation in OHQ-N2S organic crystal driven by intense terahertz fields. OPTICS LETTERS 2019; 44:4881-4884. [PMID: 31568466 DOI: 10.1364/ol.44.004881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
A laser supercontinuum is generated by cross-phase modulation (XPM) driven by an intense terahertz (THz) field in organic crystal OHQ-N2S. In this highly nonlinear medium, the THz electric field induces a time-varying optical phase modulation, which causes a spectacular spectral broadening and shifting of a co-propagating near-infrared laser pulse. The effect is enabled by the large electro-optic coefficient, the low absorption, and the good velocity matching between the laser and the THz pulse over the OHQ-N2S crystal thickness. The XPM occurs when the THz field is aligned along the polar axis of the OHQ-N2S. The results display a promising pathway for ultrafast control of the spectral and temporal properties of laser pulses using THz stimuli.
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