Band alignment at metal/ferroelectric interfaces: Insights and artifacts from first principles

Massimiliano Stengel*, Pablo Aguado-Puente, Nicola A. Spaldin, Javier Junquera

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)

Abstract

Based on recent advances in first-principles theory, we develop a general model of the band offset at metal/ferroelectric interfaces. We show that, depending on the polarization of the film, a pathological regime might occur where the metallic carriers populate the energy bands of the insulator, making it metallic. As the most common approximations of density functional theory are affected by a systematic underestimation of the fundamental band gap of insulators, this scenario is likely to be an artifact of the simulation. We provide a number of rigorous criteria, together with extensive practical examples, to systematically identify this problematic situation in the calculated electronic and structural properties of ferroelectric systems. We discuss our findings in the context of earlier literature studies, where the issues described in this work have often been overlooked. We also discuss formal analogies to the physics of polarity compensation at LaAlO3/ SrTiO3 interfaces, and suggest promising avenues for future research.

Original languageEnglish
Article number235112
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume83
Issue number23
DOIs
Publication statusPublished - 07 Jun 2011
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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