Tuning the two-dimensional electron liquid at oxide interfaces by buffer-layer-engineered redox reactions

TL;DR

This paper demonstrates how buffer-layer-engineered redox reactions can be used to create high mobility two-dimensional electron liquids at oxide interfaces, offering a new method for designing functional oxide electronic systems.

Contribution

It introduces a novel approach combining buffer layers and redox reactions to control 2DEL properties at oxide interfaces, with detailed experimental analysis.

Findings

High mobility 2DELs achieved at STO/LSMO interfaces.

Quantification of redox reactions and electronic reconstruction.

Buffer layer transformation influences 2DEL characteristics.

Abstract

Polar discontinuities and redox reactions provide alternative paths to create two-dimensional electron liquids (2DELs) at oxide interfaces. Herein, we report high mobility 2DELs at interfaces involving SrTiO3 (STO) achieved using polar La7/8Sr1/8MnO3 (LSMO) buffer layers to manipulate both polarities and redox reactions from disordered overlayers grown at room temperature. Using resonant x-ray reflectometry experiments, we quantify redox reactions from oxide overlayers on STO as well as polarity induced electronic reconstruction at epitaxial LSMO/STO interfaces. The analysis reveals how these effects can be combined in a STO/LSMO/disordered film trilayer system to yield high mobility modulation doped 2DELs, where the buffer layer undergoes a partial transformation from perovskite to brownmillerite structure. This uncovered interplay between polar discontinuities and redox reactions via buffer layers provides a new approach for the design of functional oxide interfaces.