A two-dimensional electron gas based on a 5s oxide with high room-temperature mobility and strain sensitivity

TL;DR

This paper reports a high-mobility two-dimensional electron gas on BaSnO$_3$ with strain-sensitive resistance, demonstrating potential for room-temperature oxide electronic devices.

Contribution

It introduces a 2DEG on BaSnO$_3$ with high mobility and strain sensitivity, advancing oxide electronics research.

Findings

High room-temperature mobility (~18 cm$^2$/V/s) achieved in BaSnO$_3$ 2DEG.

Strain induces a 350% resistance change at room temperature.

Observation of ferromagnetism in BaSnO$_3$ thin films.

Abstract

The coupling of optical and electronic degrees of freedom together with quantum confinement in low-dimensional electron systems is particularly interesting for achieving exotic functionalities in strongly correlated oxide electronics. Recently, high room-temperature mobility has been achieved for a large bandgap transparent oxide - BaSnO$_3$ upon extrinsic La or Sb doping, which has excited significant research attention. In this work, we report the observation of room-temperature ferromagnetism in BaSnO$_3$ thin films and the realization of a two-dimensional electron gas (2DEG) on the surface of transparent BaSnO$_3$ via oxygen vacancy creation, which exhibits a high carrier density of $\sim 7.72*10^{14} /{\rm cm}^2$ and a high room-temperature mobility of ~18 cm$^2$/V/s. Such a 2DEG is rather sensitive to strain and a less than 0.1% in-plane biaxial compressive strain leads to a giant resistance enhancement of 350% (more than 540 kOhm/Square) at room temperature. Thus, this work creates a new path to exploring the physics of low-dimensional oxide electronics and devices applicable at room temperature.