Collapse of the low temperature insulating state in Cr-doped V${}_2$O${}_3$ thin films

Abstract

We have grown epitaxial Cr-doped V${}_2$O${}_3$ thin films with Cr concentrations between $0$ and $20\%$ on $(0001)$-Al${}_2$O${}_3$ by oxygen-assisted molecular beam epitaxy. For the highly doped samples (> $3\%$), a regular and monotonous increase of the resistance with decreasing temperature is measured. Strikingly, in the low doping samples (between $1\%$ and $3\%$), a collapse of the insulating state is observed with a reduction of the low temperature resistivity by up to 5 orders of magnitude. A vacuum annealing at high temperature of the films recovers the low temperature insulating state for doping levels below $3\%$ and increases the room temperature resistivity towards the values of Cr-doped V${}_2$O${}_3$ single crystals. It is well-know that oxygen excess stabilizes a metallic state in V${}_2$O${}_3$ single crystals. Hence, we propose that Cr doping promotes oxygen excess in our films during deposition leading to the collapse of the low temperature insulating state at low Cr concentrations. These results suggest that slightly Cr-doped V${}_2$O${}_3$ films can be interesting candidates for field effect devices.

4 pages, 4 figures

References in corpus (1)

• Strain induced pressure effect in pulsed laser deposited thin films of the strongly correlated oxide V2O3

Cited by in corpus (6)

• Room temperature Mott metal-insulator transition in V2O3 compounds induced via strain-engineering
• Tuning metal-insulator transitions in epitaxial V${}_2$O${}_3$ thin films
• Early-stage dynamics of metallic droplets embedded in the nanotextured Mott insulating phase of V${}_2$O${}_3$
• Non-thermal light-assisted resistance collapse in a V${}_2$O${}_3$-based Mott-insulator device
• Ultrafast orbital manipulation and Mott physics in multi-band correlated materials
• Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V2O3 Films