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- Title
A chemically driven insulator–metal transition in non-stoichiometric and amorphous gallium oxide.
- Authors
Nagarajan, Lakshmi; De Souza, Roger A.; Samuelis, Dominik; Valov, Ilia; Börger, Alexander; Janek, Jürgen; Becker, Klaus-Dieter; Schmidt, Peter C.; Martin, Manfred
- Abstract
Insulator–metal transitions are well known in transition-metal oxides, but inducing an insulator–metal transition in the oxide of a main group element is a major challenge. Here, we report the observation of an insulator–metal transition, with a conductivity jump of seven orders of magnitude, in highly non-stoichiometric, amorphous gallium oxide of approximate composition GaO1.2 at a temperature around 670 K. We demonstrate through experimental studies and density-functional-theory calculations that the conductivity jump takes place at a critical gallium concentration and is induced by crystallization of stoichiometric Ga2O3 within the metastable oxide matrix—in chemical terms by a disproportionation. This novel mechanism—an insulator–metal transition driven by a heterogeneous solid-state reaction—opens up a new route to achieve metallic behaviour in oxides that are expected to exist only as classic insulators.
- Subjects
TRANSITION metals; METALLIC oxides; STOICHIOMETRY; GALLIUM compounds; CRYSTALLIZATION
- Publication
Nature Materials, 2008, Vol 7, Issue 5, p391
- ISSN
1476-1122
- Publication type
Article
- DOI
10.1038/nmat2164