First-Principles Modeling of Pt/LaAlO3/SrTiO3 Capacitors Under an External Bias Potential

TL;DR

This study uses first-principles simulations to analyze the electrical behavior of Pt/LaAlO3/SrTiO3 capacitors under external bias, revealing how internal fields and band structures evolve with LaAlO3 thickness and applied voltage.

Contribution

It provides a comprehensive first-principles analysis of the electrical properties of LaAlO3/SrTiO3 capacitors under bias, including band diagrams and capacitance, with implications for experimental observations.

Findings

Internal electric field decreases with LaAlO3 thickness

Spontaneous Zener tunneling is not observed in this system

Electrical characteristics depend on LaAlO3 thickness and applied bias

Abstract

We study the electrical properties of Pt/LaAlO3/SrTiO3 capacitors under the action of an external bias potential, using first-principles simulations performed at constrained electric displacement field. A complete set of band diagrams, together with the relevant electrical characteristics (capacitance and built-in fields), are determined as a function of LaAlO3 thickness and the applied potential.We find that the internal field in LaAlO3 monotonically decreases with increasing thickness; hence, the occurrence of spontaneous Zener tunneling is ruled out in this system.We discuss the implications of our results in the light of recent experimental observations on biased LaAlO3/SrTiO3 junctions involving metallic top electrodes.