Ga Sublattice Defects in (Ga,Mn)As: Thermodynamical and Kinetic Trends

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Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2004
Major/Subject
Mcode
Degree programme
Language
en
Pages
055505/1-4
Series
Physical Review Letters, Volume 93, Issue 5
Abstract
We have used positron annihilation spectroscopy and infrared absorption measurements to study the Ga sublattice defects in epitaxial Ga1−xMnxAs with Mn content varying from 0% to 5%. We show that the Ga vacancy concentration decreases and As antisite concentration increases with increasing Mn content. This is in agreement with thermodynamical considerations for the electronic part of the formation energy of the Ga sublattice point defects. However, the absolute defect concentrations imply that they are determined rather by the growth kinetics than by the thermodynamical equilibrium. The As antisite concentrations in the samples are large enough to be important for compensation and magnetic properites. In addition, the Ga vacancies are likely to be involved in the diffusion and clustering of Mn at low annealing temperatures.
Description
Keywords
GaMnAs, defects, compensation
Other note
Citation
Tuomisto, Filip & Pennanen, K. & Saarinen, K. & Sadowski, J. 2004. Ga Sublattice Defects in (Ga,Mn)As: Thermodynamical and Kinetic Trends. Physical Review Letters. Volume 93, Issue 5. 055505/1-4. ISSN 0031-9007 (printed). DOI: 10.1103/physrevlett.93.055505