Enhanced spin-orbit coupling and charge carrier density suppression in LaAl1-xCrxO3/SrTiO3 heterointerfaces

TL;DR

This study investigates how substituting chromium into LaAlO3/SrTiO3 heterointerfaces suppresses the 2DEG, increases resistance, and enhances spin-orbit coupling, revealing tunable electronic properties in oxide interfaces.

Contribution

It demonstrates the effect of Cr substitution on 2DEG suppression and charge carrier modulation at LaAlO3/SrTiO3 interfaces, highlighting a new method to control interfacial electronic behavior.

Findings

Sheet carrier density drops significantly with Cr substitution.

Sheet resistance exceeds quantum limit at high Cr concentrations.

Cr substitution enhances spin-orbit coupling effects.

Abstract

We report a gradual suppression of the two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 interface on substitution of chromium at the Al sites. The sheet carrier density at the interface (ns) drops monotonically from 2.2x10(14) cm-2 to 2.5x10(13) cm-2 on replacing nearly 60 percent of Al sites by Cr and the sheet resistance (Rs) exceeds the quantum limit for localization (h/2e2) in the concentrating range 40 to 60 percent of Cr.