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

TL;DR

This study investigates how electrochemical etching affects the transport properties of ultrathin SrVO3 films, revealing a transition from metallic to insulating behavior near 3 monolayers due to increased scattering and weak anti-localization effects.

Contribution

It demonstrates a method to fabricate ultrathin SrVO3 films with controlled thickness and explores the transport property evolution near the metal-insulator transition.

Findings

Metallic behavior maintained down to 3 ML after etching

Electron mobility decreases with thickness below 10 ML

Observation of weak anti-localization effects at low temperatures

Abstract

By using electrochemical etching, we fabricated conductive ultrathin SrVO3 (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 anti-localization of electrons in a weakly disordered metal.