A chemically driven insulator-metal transition in non-stoichiometric and amorphous gallium oxide

Lakshmi Nagarajan; Roger A De Souza; Dominik Samuelis; Ilia Valov; Alexander Börger; Jürgen Janek; Klaus-Dieter Becker; Peter C Schmidt; Manfred Martin

doi:10.1038/nmat2164

A chemically driven insulator-metal transition in non-stoichiometric and amorphous gallium oxide

Lakshmi Nagarajan, Roger A De Souza, Dominik Samuelis, Ilia Valov, Alexander Börger, Jürgen Janek, Klaus-Dieter Becker, Peter C Schmidt, Manfred Martin

Research output: Contribution to journal › Article › peer-review

179 Citations (Scopus)

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 GaO(1.2) 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 Ga(2)O(3) 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.

Original language	English
Pages (from-to)	391-398
Number of pages	8
Journal	Nature Materials
Volume	7
Issue number	5
DOIs	https://doi.org/10.1038/nmat2164
Publication status	Published - May 2008
Externally published	Yes

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title = "A chemically driven insulator-metal transition in non-stoichiometric and amorphous gallium oxide",

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 GaO(1.2) 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 Ga(2)O(3) 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.",

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T1 - A chemically driven insulator-metal transition in non-stoichiometric and amorphous gallium oxide

AU - Nagarajan, Lakshmi

AU - De Souza, Roger A

AU - Samuelis, Dominik

AU - Valov, Ilia

AU - Börger, Alexander

AU - Janek, Jürgen

AU - Becker, Klaus-Dieter

AU - Schmidt, Peter C

AU - Martin, Manfred

PY - 2008/5

Y1 - 2008/5

N2 - 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 GaO(1.2) 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 Ga(2)O(3) 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.

AB - 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 GaO(1.2) 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 Ga(2)O(3) 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.

U2 - 10.1038/nmat2164

DO - 10.1038/nmat2164

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JO - Nature Materials

JF - Nature Materials

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ER -

A chemically driven insulator-metal transition in non-stoichiometric and amorphous gallium oxide

Abstract

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