Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface

TL;DR

This paper reports the creation of a high-mobility two-dimensional electron gas at a nonpolar oxide interface induced by epitaxial strain, with potential applications in nanoelectronics.

Contribution

It demonstrates a novel method to generate 2DEGs via strain-induced polarization at nonpolar oxide interfaces, achieving record electron mobility.

Findings

Electron mobility exceeds 60,000 cm²V⁻¹s⁻¹ at low temperatures.

The 2DEG carrier density depends critically on film thickness.

The interface is atomically sharp and exhibits polarization-induced 2DEG characteristics.

Abstract

The discovery of two-dimensional electron gases (2DEGs) in SrTiO3-based heterostructures provides new opportunities for nanoelectronics. Herein, we create a new type of oxide 2DEG by the epitaxial-strain-induced polarization at an otherwise nonpolar perovskite-type interface of CaZrO3/SrTiO3. Remarkably, this heterointerface is atomically sharp, and exhibits a high electron mobility exceeding 60,000 cm2V-1s-1 at low temperatures. The 2DEG carrier density exhibits a critical dependence on the film thickness, in good agreement with the polarization induced 2DEG scheme.