Metallicity at interphase boundaries due to polar catastrophe induced by charge density discontinuity

Arwa Albar, Hassan Ali Tahini, Udo Schwingenschlögl

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The electronic properties of interphase boundaries are of basic importance for most materials, particularly when those properties deviate strongly from the bulk behavior. We introduce a mechanism that can result in metallicity at stoichiometric interphase boundaries between semiconductors based on the idea of polar catastrophe, which is usually considered only in the context of heterostructures. To this end, we perform ab initio calculations within density functional theory to investigate the electronic states at stoichiometric SnO/SnO2 (110) interphase boundaries. In this system, one would not expect polar catastrophe to have a role according to state-of-the-art theory because the interface lacks formal charge discontinuity. However, we observe the formation of a hole gas between the semiconductors SnO and SnO2. To explain these findings, we provide a generalized theory based on the idea that the charge density discontinuity between SnO and SnO2, a consequence of lattice mismatch, drives a polar catastrophe scenario. As a result, SnO/SnO2 (110) interphase boundaries can develop metallicity depending on the grain size. The concept of metallicity due to polar catastrophe induced by charge density discontinuity is of general validity and applies to many interphase boundaries with lattice mismatch.
Original languageEnglish (US)
Pages (from-to)e469-e469
Number of pages1
JournalNPG Asia Materials
Volume10
Issue number2
DOIs
StatePublished - Feb 9 2018

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