Metallicity of the SrTiO3 surface induced by room temperature evaporation of alumina

TL;DR

This study demonstrates that the surface of SrTiO3 can be made metallic through room temperature evaporation of alumina or granular aluminium, with the surface state controllable by oxygen pressure, without special preparation.

Contribution

It introduces a simple method to induce and control metallic states on SrTiO3 surfaces using room temperature evaporation of alumina or granular aluminium.

Findings

Metallic surface states achieved without heating or special prep

Surface state controlled by oxygen pressure during evaporation

Photoconductivity and field effect demonstrated

Abstract

It is shown that a metallic state can be induced on the surface of SrTiO3 crystals by the electron beam evaporation of oxygen deficient alumina or insulating granular aluminium. No special preparation nor heating of the SrTiO3 surface is needed. Final metallic or insulating states can be obtained depending on the oxygen pressure during the evaporation process. Photoconductivity and electrical field effect are also demonstrated.