Decoupling of Structural and Electronic Phase Transitions in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>VO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>

Tao, Zhensheng; Han, Tzong Ru T; Mahanti, S. D.; Duxbury, Phillip M.; Yuan, Fei; Ruan, Chong‐Yu; Wang, Kevin; Wu, Junqiao

doi:10.1103/physrevlett.109.166406

Cited by 155 publications

(132 citation statements)

References 29 publications

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“…Our results are specific to VO 2 , yet universally relatable to other correlated electron materials [75]. Previously studied VO 2 nano-beams and micro-crystals can be regarded as specific cases with some of the unique strain environments identified in the present study [23][24][25]76]. In future studies, ultrafast femtosecond dynamics [77][78][79] and magnetic orders [1] can also be included in systematic near-field investigations of TMOs, which will lead to a better understanding of the rich diversity of mesoscopic and microscopic phenomena at fundamental time and length scales in materials such as manganites and high temperature superconductors.…”

Section: Discussionsupporting

confidence: 65%

Phase transition in bulk single crystals and thin films ofVO2by nanoscale infrared spectroscopy and imaging

et al. 2015

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We have systematically studied a variety of vanadium dioxide (VO 2 ) crystalline forms, including bulk single crystals and oriented thin films, using infrared (IR) near-field spectroscopic imaging techniques. By measuring the IR spectroscopic responses of electrons and phonons in VO 2 with sub-grain-size spatial resolution (~20 nm), we show that epitaxial strain in VO 2 thin films not only triggers spontaneous local phase separations but also leads to intermediate electronic and lattice states that are intrinsically different from those found in bulk. Generalized rules of strain and symmetry dependent mesoscopic phase inhomogeneity are also discussed. These results set the stage for a comprehensive understanding of complex energy landscapes that may not be readily determined by macroscopic approaches.

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Section: Discussionsupporting

confidence: 65%

Phase transition in bulk single crystals and thin films ofVO2by nanoscale infrared spectroscopy and imaging

et al. 2015

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“…The exact nature of the metal-insulator transition has remained elusive and is of continuing scientific interest; recent work has emphasized the significance of electronelectron interactions associated with a Mott-Hubbard transition and/or electron-phonon interactions associated with a Peierls mechanism. [2][3][4][5][6][7][8][9] The value of τ c can be changed by substitutional doping, for example by replacing some vanadium by tungsten, 10 and wellcrystallized W x V 1-x O 2 films with x ≈ 0.02 can have τ c ≈ 20 °C; 11 doping with atomic hydrogen is another possibility. 12 The magnitude of the resistance change at τ c depends on the degree of crystallinity, and epitaxial films can display a difference of three to four orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling

Namura

Suzuki

et al. 2013

Journal of Applied Physics

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Thermochromic VO 2 nanorods made by sputter deposition: Growth conditions and optical modeling. Reactive dc magnetron sputtering onto glass-based substrates yielded deposits of thermochromic VO 2 with well-developed nanorods and nanowires. Their formation was promoted by high substrate temperature (above ~500 °C), sufficient film thickness, proper inlet of the reactive gas, dispersed gold "seeds" and pronounced substrate roughness. Rutherford back scattering ascertained mass thicknesses, scanning electron microscopy depicted the nanostructures, and glancing incidence Xray diffraction proved that single-phase VO 2 was normally formed. Journal of Applied PhysicsSpectrophotometric measurements of total and diffuse transmittance and reflectance on VO 2 thin films, at room temperature and ~100 °C, allowed us to determine complex dielectric functions below and above the "critical" temperature for thermochromic switching (~68 °C). These data were then used in computations based on the Bruggeman effective medium theory applied to randomly oriented prolate spheroidal structural units to derive the optical properties of the deposits.Experimental and computed data on spectral absorptance were found to be in good qualitative agreement.

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“…Despite many ultrafast and static measurements, the exact mechanisms responsible for the IMTs in vanadium oxides and especially in VO 2 remain widely debated [19][20][21][22][23][24][25][26][27] , namely the contribution of electronic correlations (Mott-Hubbard picture) and of electron-lattice mediated effects (Peierls model) 17,23,[28][29][30] . It is clear, however, that multiple pathways are possible to initiate pressure and temperature dependent transitions, and that electronic and lattice effects are strongly coupled 17,28,31,32 .…”

Section: Introductionmentioning

confidence: 99%

Ultrafast electron-lattice coupling dynamics in VO2 and V2O3 thin films

et al. 2017

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Ultrafast optical pump -optical probe and optical pump -terahertz probe spectroscopy were performed on vanadium dioxide (VO 2 ) and vanadium sesquioxide (V 2 O 3 ) thin films over a wide temperature range. A comparison of the experimental data from these two different techniques and two different vanadium oxides, in particular a comparison of the spectral weight oscillations generated by the photoinduced longitudinal acoustic modulation, reveals the strong electron-phonon coupling that exists in both materials. The low energy Drude response of V 2 O 3 appears more amenable than VO 2 to ultrafast strain control. Additionally, our results provide a measurement of the temperature dependence of the sound velocity in both systems, revealing a four-to fivefold increase in VO 2 and a three-to fivefold increase in V 2 O 3 across the insulator-to-metal phase transition. Our data also confirm observations of strong damping and phonon anharmonicity in the metallic phase of VO 2 , and suggest that a similar phenomenon might be at play in the metallic phase of V 2 O 3 . More generally, our simple table-top approach provides relevant and detailed information about dynamical lattice properties of vanadium oxides, paving the way to similar studies in other complex materials.2

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Decoupling of Structural and Electronic Phase Transitions inVO2

Cited by 155 publications

References 29 publications

Phase transition in bulk single crystals and thin films ofVO2by nanoscale infrared spectroscopy and imaging

Phase transition in bulk single crystals and thin films ofVO2by nanoscale infrared spectroscopy and imaging

Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling

Ultrafast electron-lattice coupling dynamics in VO2 and V2O3 thin films

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