Termination Control of the Interface Dipole in La$_{0.7}$Sr$_{0.3}$MnO$_3$/Nb:SrTiO$_3$ (001) Schottky Junctions

TL;DR

This study demonstrates how the interface termination in La$_{0.7}$Sr$_{0.3}$MnO$_3$/Nb:SrTiO$_3$ junctions influences the Schottky barrier height through control of the interface dipole, enabling tunable band alignments in oxide heterostructures.

Contribution

It introduces a method to control the interface dipole and band alignment in oxide heterostructures by varying the termination layer at the interface.

Findings

Schottky barrier height increases with SrO termination

Interface dipole evolution screens polar discontinuity

Tuning interface termination controls band alignment

Abstract

In order to investigate the interface termination dependence of perovskite band alignments, we have studied the Schottky barrier height at La$_{0.7}$Sr$_{0.3}$MnO$_3$/Nb:SrTiO$_3$ (001) heterointerfaces. As the Nb:SrTiO$_3$ semiconductor was varied from TiO$_2$ termination to SrO termination by variable insertion of a SrMnO$_3$ layer, a large systematic increase in the Schottky barrier height was observed. This can be ascribed to the evolution of the interface dipole induced to screen the polar discontinuity at the interface, which gives a large internal degree of freedom for tuning band diagrams in oxides.