Metal-insulator transition in SrTi1−xVxO3 thin films

Abstract

x ≤ 1) thin films with thicknesses of ∼ 16 nm were grown on (001)-oriented LSAT substrates using the pulsed electron-beam deposition technique. The transport study revealed a temperature driven metal-insulator transition (MIT) at 95 K for the film with x = 0.67. The films with higher vanadium concentration (x >0.67) were metallic, and the electrical resistivity followed the T 2 law corresponding to a Fermi liquid system. In the insulating region of x <0.67, the temperature dependence of electrical resistivity for the x = 0.5 and 0.33 films can be scaled with Mott's variable range hopping model. The possible mechanism behind the observed MIT might be associated the interplay between electron-electron interactions and disorder-induced localization. The Ti 4+ ion substitution introduces Anderson-localized states as well as lattice distortions that result in a reduction in the effective 3d bandwidth W.

Compromising Between Phase Stability and Electrical Performance: SrVO3–SrTiO3 Solid Solutions as Solid Oxide Fuel Cell Anode Components

“…The observed trends in variation of electrical conductivity in the high‐temperature range are in agreement with the literature data on the low‐temperature resistivity measurements. It has been reported that the electrical resistivity in SrV 1− y Ti y O 3− δ system at T ≤300 K decreases with increasing V content, whereas the metal–insulator transition was observed at y ≈0.3–0.4 . One may expect, therefore, that the composition with y= 0.5 should undergo metal–semiconductor transition between room temperature and 340 °C.…”

“…[68][69][70][71] On the other hand, Ti 4 + cations have no de lectrons, and stoichiometric SrTiO 3 is aw ide-bandgap semiconductor. [50] The substitution of Vb yT ir esults in ap erturbation of the conduction band, a gradualn arrowing of the effective bandwidth, and, eventually, localization of electronic charge carriers [49][50][51] accompanied by a decreaseintheir concentration. As aresult, the Ti-rich solid solutions demonstrate semiconducting behavior with the electronic transport contributed, most likely,b ye lectron hopping between V 4 + /V 3 + pairs.…”

“…The approach employed in this work is to introduce Ti into the V sublattice of SrVO 3 to enhance its stability under more oxidizing conditions. SrVO 3 and SrTiO 3 both have a cubic perovskite structure from their melting points down to room temperatures and have been reported to form an entire range of solid solutions . Existing studies of the SrVO 3 –SrTiO 3 system include the measurements of electrical resistivity, magnetic susceptibility, and Hall effects at temperatures ≤300 K employing polycrystalline samples, single crystals and thin films .…”

“…SrVO 3 and SrTiO 3 both have ac ubic perovskite structure from their melting points down to room temperatures and have been reported to form an entire range of solid solutions. [49][50][51] Existing studies of the SrVO 3 -SrTiO 3 system include the measurements of electrical resistivity,m agnetic susceptibility,a nd Hall effects at temperatures 300 Ke mploying polycrystalline samples, [49] single crystals [50] and thin films. [51] In the present work, an emphasis was given to the high-temperature properties of solid solutions, including phase stability,e lectrical transport, variable oxygen content,redox behavior,a nd thermochemical expansion.…”

Surface Characterizations and Selective Etching of Sr‐Rich Segregation on Top of SrVO3 Thin‐Films Grown by Pulsed Laser Deposition

“…State of the art SVO thin‐films grown by pulsed laser deposition (PLD) onto SrTiO 3 (STO) (100) have a RRR of 2.4, which is much lower compared to hybrid‐MBE deposition technique ,. Since PLD is a most common technique for complex oxides, process conditions to perform an efficient SVO thin‐film are taken under strong interest ,,. In this regard, oxygen is particularly known as a crucial parameter leading for instance to the creation of a Metal Insulator Transition (MIT) in other perovskite compounds for STO, and LaNiO 3 ,,.…”