Lattice polarization effects on electron-gas charge densities in ionic superlattices

TL;DR

This paper investigates how lattice polarization influences electron-gas charge densities in ionic superlattices, emphasizing the importance of electron-phonon interactions and anharmonic effects for accurate modeling.

Contribution

It introduces a model incorporating lattice polarization effects and temperature dependencies to better understand 2D electron gases in oxide superlattices.

Findings

Charge distribution is strongly affected by electron-phonon interactions.

Anharmonic effects are essential for matching experimental observations.

The model predicts temperature-dependent behavior of electron gases.

Abstract

The atomic-level control achievable in artificially-structured oxide superlattices provides a unique opportunity to explore interface phases of matter including high-density 2D electron gases. Electronic-structure calculations show that the charge distribution of the 2D gas is strongly modulated by electron-phonon interactions with significant ionic polarization. Anharmonic finite-temperature effects must be included to reproduce experiment. Density functional perturbation theory is used to parameterize a simple model introduced to represent these effects and predict temperature dependencies.