Electron localization induced by intrinsic anion disorder in a transition metal oxynitride

Daichi Oka, Yasushi Hirose, Shoichiro Nakao, Tomoteru Fukumura, Tetsuya Hasegawa

Research output: Contribution to journalArticlepeer-review

Abstract

Anderson localization derived from randomness plays a crucial role in various kinds of phase transitions. Although treated as a free variable parameter in theory, randomness in electronic materials is hard to control experimentally owing to the coexisting Coulomb interaction. Here we demonstrate that the intrinsic anion disorder in a mixed-anion system of SrNbO2N induces a significant random potential that overwhelms the Coulomb potential while maintaining the lattice structure. A metal-to-insulator transition is triggered by a chemical modulation of the electron density where the critical electron density is more than three orders of magnitude greater than that predicted by the well-known Mott criterion. The localized electrons show characteristic electrical properties such as temperature-dependent multiple crossovers of conduction mechanisms and a positive magnetoresistance above 50% at low temperature. The large magnetoresistance is attributed to wave-function shrinkage of the localized states and clearly visualizes the anisotropy in the band structure, which indicates a compatibility of the periodicity and randomness.

Original languageEnglish
Article number269
JournalCommunications Physics
Volume4
Issue number1
DOIs
Publication statusPublished - 2021 Dec

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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