Antisite effect on ferromagnetism in (Ga,Mn)As

Myers, R. C.; Sheu, B. L.; Jackson, A. W.; Gossard, A. C.; Schiffer, P.; Samarth, N.; Awschalom, D. D.

Antisite effect on ferromagnetism in (Ga,Mn)As

Authors

Description

We study the Curie temperature and hole density of (Ga,Mn)As while systematically varying the As-antisite density. Hole compensation by As-antisites limits the Curie temperature and can completely quench long-range ferromagnetic order in the low doping regime of 1-2% Mn. Samples are grown by molecular beam epitaxy without substrate rotation in order to smoothly vary the As to Ga flux ratio across a single wafer. This technique allows for a systematic study of the effect of As stoichiometry on the structural, electronic, and magnetic properties of (Ga,Mn)As. For concentrations less than 1.5% Mn, a strong deviation from Tc ~ p^0.33 is observed. Our results emphasize that proper control of As-antisite compensation is critical for controlling the Curie temperatures in (Ga,Mn)As at the low doping limit.
10 pages, 7 figures