title: Entropy-driven stabilization of a novel configuration for acceptor-hydrogen complexes in GaN.
abstract: We present a model for the microscopic structure of Mg-H complexes in GaN, explaining the unusual bond angle observed in recent vibrational spectroscopy studies. The structure is not the lowest-energy configuration at T = 0, but it is stabilized at elevated temperatures due to the large entropy associated with a set of low-energy rotational excitations. The rotational excitation spectrum is calculated using a quantum-mechanical model in which the hydrogen atom moves in a weak corrugation potential. Consequences for experiment are discussed.
authors.affiliation: Xerox Palo Alto Research Center, 3333 Coyote Hill Road, Palo Alto, California 94304.
authors.forename: S
authors.initials: S
authors.lastname: Limpijumnong
authors.forename: J E
authors.initials: JE
authors.lastname: Northrup
authors.forename: C G
authors.initials: CG
authors.lastname: Van De Walle