Temperature dependence of thermal conductivity of VO<sub>2</sub>thin films across metal–insulator transition

Kizuka, Hinako; Yagi, Takashi; Jia, Junjun; Yamashita, Yuichiro; Nakamura, Shigenari; Taketoshi, Naoyuki; Shigesato, Yuzo

doi:10.7567/jjap.54.053201

Cited by 81 publications

(54 citation statements)

References 22 publications

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“…Metal-insulator transitions: Metal-insulator transitions (MITs) dramatically change the electrical conductivity r. In the best-known example, r can increase by 5 orders of magnitude when vanadium dioxide crosses a MIT around T MIT ¼ 340 K. It is natural to suspect that the thermal conductivity of VO 2 may also show a large change across the MIT, since the standard single-electron Wiedemann-Franz (WF) law (Lorenz number L ¼ L 0 ¼ 2.44 Â 10 À8 WX/K 2 ) predicts that both electrons and phonons contribute significantly to k in the metallic state, while in the insulating state only the phonon k remains. Indeed, several experiments 22,23 have measured switch ratios as large as r ¼ 1.6 in polycrystalline VO 2 films. However, these experiments measured k in the cross-plane direction and r in the in-plane direction, so the WF law could not be quantitatively tested.…”

Section: Changes In K Due To Phase Transitionsmentioning

confidence: 99%

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Wehmeyer

Yabuki

Monachon

et al. 2017

Applied Physics Reviews

377

261

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Interest in new thermal diodes, regulators, and switches has been rapidly growing because these components have the potential for rich transport phenomena that cannot be achieved using traditional thermal resistors and capacitors. Each of these thermal components has a signature functionality: Thermal diodes can rectify heat currents, thermal regulators can maintain a desired temperature, and thermal switches can actively control the heat transfer. Here, we review the fundamental physical mechanisms of switchable and nonlinear heat transfer which have been harnessed to make thermal diodes, switches, and regulators. The review focuses on experimental demonstrations, mainly near room temperature, and spans the fields of heat conduction, convection, and radiation. We emphasize the changes in thermal properties across phase transitions and thermal switching using electric and magnetic fields. After surveying fundamental mechanisms, we present various nonlinear and active thermal circuits that are based on analogies with well-known electrical circuits, and analyze potential applications in solid-state refrigeration and waste heat scavenging.

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Section: Changes In K Due To Phase Transitionsmentioning

confidence: 99%

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Wehmeyer

Yabuki

Monachon

et al. 2017

Applied Physics Reviews

377

261

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“…Also, VO 2 has a monoclinic structure at low temperature under 340 K, while it is tetragonal at higher temperatures 29,30 . During the structural transition of NbO 2 and VO 2 , their σ e increase undergoing semiconductor/metal (S/M) transition, increasing thermal conductivities as shown in Fig.…”

Section: Bulkmentioning

confidence: 99%

Thermal conductivity switch: Optimal semiconductor/metal melting transition

Kim

Kaviany

2016

Phys. Rev. B

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Scrutinizing distinct solid/liquid (s/l) and solid/solid (s/s) phase transitions (passive transitions) for large change in bulk (and homogenous) thermal conductivity, we find the s/l semiconductor/metal (S/M) transition produces largest dimensionless thermal conductivity switch (TCS) figure of merit Z TCS (change in thermal conductivity divided by smaller conductivity). At melting temperature, the solid phonon and liquid molecular thermal conductivities are comparable and generally small, so the TCS requires localized electron solid and delocalized electron liquid states.For cyclic phase reversibility, the congruent phase transition (no change in composition) is as important as the thermal transport. We identify XSb and XAs (X = Al, Cd, Ga, In, Zn) and describe atomic-structural metrics for large Z TCS , then show the superiority of S/M phonon-to electrondominated transport melting transition. We use existing experimental results and theoretical and ab initio calculations of the related properties for both phases (including the Kubo-Greenwood and Bridgman formulations of liquid conductivities). The 5p orbital of Sb contributes to the semiconductor behavior in the solid-phase bandgap and upon disorder and bond-length changes in the liquid phase this changes to metallic, creating the large contrast in thermal conductivity.The charge density distribution, electronic localization function, and electron density of states are used to mark this S/M transition. For optimal TCS, we examine the elemental selection from the transition-, basic-and semimetals and semiconductor groups. For CdSb, addition of residual Ag suppresses the bipolar conductivity and its Z TCS is over 7, and for Zn 3 Sb 2 it is expected to be over 14, based on the structure and transport properties of the better known β-Zn 4 Sb 3 . This is the highest Z TCS identified. In addition to the metallic melting, the high Z TCS is due to the electron-poor nature of II-V semiconductors leading to the significantly low phonon conductivity.

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“…VO 2 is well known for its reversible insulator to metallic transition accompanied by structural phase transition. [22,23] To confirm our proposed approach, we have performed a thorough nanotribological characterization on VO 2 platelets by FFM and nanoindentation scratch tests. This phase transition in VO 2 can be achieved by a number of stimuli-like temperature, electrical current, or mechanical pressure.…”

Section: Introductionmentioning

confidence: 98%

Switchable Friction across Insulator–Metal Transition in VO₂

et al. 2019

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Significant friction turnover across the insulator to metal phase transition of VO 2 microcrystals as measured by friction force microscopy (FFM) and nanoscratch experiments is reported. Insulator to metal transition in chemical vapor deposition-grown VO 2 platelet is confirmed by in situ Raman investigations and electrical resistance measurements that show more than four orders of magnitude change in electrical resistance across transition temperature. The coefficient of friction (COF) for the high-temperature metallic phase, that is about two times higher than that of room-temperature insulating phase, is demonstrated. To avoid temperature effects on friction, the friction of coexisting insulating and metallic phases at a constant temperature of %69 C is measured. Additionally, the results also show that this twofold increase in COF is fully reversible when the phase transition is triggered by a heating-cooling cycle and can potentially be used as tuneable friction-based gripping systems.

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Temperature dependence of thermal conductivity of VO₂thin films across metal–insulator transition

Cited by 81 publications

References 22 publications

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Thermal conductivity switch: Optimal semiconductor/metal melting transition

Switchable Friction across Insulator–Metal Transition in VO₂

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Temperature dependence of thermal conductivity of VO2thin films across metal–insulator transition

Cited by 81 publications

References 22 publications

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Thermal diodes, regulators, and switches: Physical mechanisms and potential applications

Thermal conductivity switch: Optimal semiconductor/metal melting transition

Switchable Friction across Insulator–Metal Transition in VO2

Contact Info

Product

Resources

About

Temperature dependence of thermal conductivity of VO₂thin films across metal–insulator transition

Switchable Friction across Insulator–Metal Transition in VO₂