title: Mn interstitial diffusion in (ga,mn)as.
abstract: We present a combined theoretical and experimental study of the ferromagnetic semiconductor (Ga,Mn)As which explains the remarkably large changes observed on low-temperature annealing. Careful control of the annealing conditions allows us to obtain samples with ferromagnetic transition temperatures up to 159 K. Ab initio calculations, in situ Auger spectroscopy, and resistivity measurements during annealing show that the observed changes are due to out diffusion of Mn interstitials towards the surface, governed by an energy barrier of 0.7-0.8 eV. Electric fields induced by Mn acceptors have a significant effect on the diffusion.
authors.affiliation: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
authors.forename: K W
authors.initials: KW
authors.lastname: Edmonds
authors.forename: P
authors.initials: P
authors.lastname: Bogusławski
authors.forename: K Y
authors.initials: KY
authors.lastname: Wang
authors.forename: R P
authors.initials: RP
authors.lastname: Campion
authors.forename: S N
authors.initials: SN
authors.lastname: Novikov
authors.forename: N R S
authors.initials: NR
authors.lastname: Farley
authors.forename: B L
authors.initials: BL
authors.lastname: Gallagher
authors.forename: C T
authors.initials: CT
authors.lastname: Foxon
authors.forename: M
authors.initials: M
authors.lastname: Sawicki
authors.forename: T
authors.initials: T
authors.lastname: Dietl
authors.forename: M
authors.initials: M
authors.lastname: Buongiorno Nardelli
authors.forename: J
authors.initials: J
authors.lastname: Bernholc