Special Quasi-ordered Structures: role of short-range order in the semiconductor alloy (GaN)\(_{1-x}\)(ZnO)\(_x\)

This paper studies short-range order (SRO) in the semiconductor alloy (GaN)\(_{1-x}\)(ZnO)\(_x\). Monte Carlo simulations performed on a density functional theory (DFT)-based cluster expansion model show that the heterovalent alloys exhibit strong SRO because of the energetic preference for the vale...

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Bibliographic Details
Published inarXiv.org
Main Authors Liu, Jian, Fernández-Serra, Maria V, Allen, Philip B
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 09.12.2015
Subjects
Alloy development
Alloys
Bonding strength
Bowing
Computer simulation
Density functional theory
Gallium nitrides
Intermetallic compounds
Lattice vibration
Short range order
Zinc oxide
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Summary:This paper studies short-range order (SRO) in the semiconductor alloy (GaN)\(_{1-x}\)(ZnO)\(_x\). Monte Carlo simulations performed on a density functional theory (DFT)-based cluster expansion model show that the heterovalent alloys exhibit strong SRO because of the energetic preference for the valence-matched nearest-neighbor Ga-N and Zn-O pairs. To represent the SRO-related structural correlations, we introduce the concept of Special Quasi-ordered Structure (SQoS). Subsequent DFT calculations reveal dramatic influence of SRO on the atomic, electronic and vibrational properties of the (GaN)\(_{1-x}\)(ZnO)\(_x\) alloy. Due to the enhanced statistical presence of the energetically unfavored Zn-N bonds with the strong Zn3\(d\)-N2\(p\) repulsion, the disordered alloys exhibit much larger lattice bowing and band-gap reduction than those of the short-range ordered alloys. Inclusion of lattice vibrations stabilizes the disordered alloy.
ISSN:2331-8422
DOI:10.48550/arxiv.1505.06329