Transport properties around the metal-insulator transition for SrVO3 ultrathin films fabricated by electrochemical etching

Abstract

By using electrochemical etching, we fabricated conductive ultrathin ${\mathrm{SrVO}}_{3}$ (SVO) films that exhibited metallic behavior down to 3 monolayers (ML). From an observed systematic change in transport properties with decreasing film thickness, it was found that the disorder in the films remained nearly unchanged during etching, and only the thickness was reduced. This is in contrast to the insulating behavior found for as-deposited SVO ultrathin films. For the etched films, the electron mobility at 200 K decreased with decreasing film thickness below 10 ML, originating from an increased scattering rate and electron effective mass near the metal-insulator transition. A slight upturn in the resistivity and a positive magnetoresistance at low temperatures were typically observed for the etched films down to 3 ML, which was explained by weak antilocalization of electrons in a weakly disordered metal.