Metal-insulator transition with multiple micro-scaled avalanches in VO2 thin film on TiO2(001) substrates

Abstract

We observed micro-scale phase separation in VO2 thin films on TiO2(001) substrates and investigated the relationship between the appearance of metallic domains and the abrupt resistive changes around the phase transition. The resistive changes are interpreted using a combined resistance model of the two phases, and the conductance evaluated from the visualized domain behavior was consistent with the electronic properties. These results indicate the importance of modifying conductive behavior spatially using a partial phase transition.

TiO2(R)/VO2(M)/TiO2(A) multilayer film as smart window: Combination of energy-saving, antifogging and self-cleaning functions

“…[8] The idea of using VO 2 (M) for a smart window can be realized because $ 40 1C of T c has been attained by various dopings, in which the replacement of V 4 + by a small amount of penta-or hexavalent ions seems to be the most effective. [9,10] Currently, to fabricate VO 2 (M) based films, several methods have been applied, such as wet chemical approaches [11,12], chemical vapor deposition (CVD) [13][14][15], pulsed laser deposition (PLD) [16,17] and magnetron sputtering (MS) [18][19][20].…”

“…Due to similar lattice parameters, TiO 2 (R) films are acted as buffer layer and growth template of VO 2 (M) films. [17] Nevertheless, TiO 2 (R) films are less efficient photocatalysts than anatase TiO 2 (TiO 2 (A)) films, which occupy an important position in the studies of photocatalytic active.…”

Dynamic phase coexistence and non-Gaussian resistance fluctuations inVO2near the metal-insulator transition

“…This observation being a new component adds a separate dimension to the MIT in this material. The local decoupling of electron temperature from the lattice temperature may provide the genesis for the electric field driven MIT and avalanche break down in microscale VO 2 structures reported recently 9,14,15,24 . The noise spectroscopy along with high precision resistance data provide evidence that there is likely occurrence of more than two phases reported recently in elastic experiments on VO 2 nano-beams 11 .…”

“…The magnitude of local deviation of the electron temperature will depend on thermal quantities like specific heat of the co-existing phases as well as thermal conductivity that can ensure efficient heat transfer from the regions of high current density. In recent years there are reports of voltage driven MIT in VO 2 films as well as avalanche type break down 24 . We propose that genesis of such phenomena can lie at the local departure of the electron temperature from the equilibrium lattice bath as has been directly observed by Nyquist noise thermometry.…”

Local Peltier-effect-induced reversible metal–insulator transition in VO2 nanowires

“…By reducing the sample size to a single domain, on the other hand, a steep first-order phase transition for individual domains can be observed. [10][11][12] Regarding the characteristics of the phase transition, ultra-fast 13 and spatial avalanche transitions in domains 10,14,15 have been reported. Thus, electronic control of the transition in the two terminal devices has much attracted attention; 9,[16][17][18][19] however, the control enables only a one-way transition, from insulator to metal (I-to-M).…”