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arXiv · 1108.1166

Phase-separated high-temperature-annealed (Ga,Mn)As: A negative charge-transfer-energy material

M. Moreno·K. H. Ploog
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Abstract

The approximate location in the Zaanen-Sawatzky-Allen diagram of the phase-separated (Ga,Mn)As material, consisting of MnAs nanoclusters embedded in GaAs, is determined on the basis of configuration-interaction (CI) cluster-model analysis of their Mn 2p core-level photoemission. The composite material is found to belong to the special class of materials with negative charge-transfer energy (delta). As such, its metallic or insulating/semiconducting behavior depends on the strength of the p-d hybridization (affected by strain) relative to the (size-dependent) p-bandwidth. Whereas internal strain in the embedded clusters counteracts gap opening, a metal-to-semiconductor transition is expected to occur for decreasing cluster size, associated to the opening of a small gap of p-p type (covalent gap). The electronic properties of homogeneous and phase-separated (Ga,Mn)As materials are analyzed, with emphasis on the nature of their metal-insulator transitions.

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M. Moreno, K. H. Ploog. 2011-08-04. Phase-separated high-temperature-annealed (Ga,Mn)As: A negative charge-transfer-energy material. https://arxiv.org/abs/1108.1166

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