https://doi.org/10.1140/epjb/e2012-30785-6
Regular Article
Band modification in (Ga, Mn)As evidenced by new measurement scheme – photoresistance magnetic circular dichroism
State Key Laboratory for Superlattices and
Microstructures, Institute of Semiconductors, Chinese Academy of Sciences,
P.O. Box 912,
Beijing
100083, P.R.
China
a e-mail: hzzheng@red.semi.ac.cn
Received:
29
August
2012
Published online:
22
November
2012
A new scheme for measuring magneto-optical (MO) effect is developed in the present work, called photoresistance magnetic circular dichroism (PR-MCD). It detects the differential photoresistance of materials between two circularly polarized excitations. That allows us to detect the MO effect induced mainly by interband transitions, as evidenced by the appearance of a clear long wavelength cutoff at 840 nm in PR-MCD spectrum. Our results provide unambiguous evidence that the host semiconductor band structure of (Ga, Mn)As is indeed modified by the strong exchange interactions. It is also found that the interband-induced MO effect decays rather fast with increasing temperatures as compared to MO effects observed in conventional MCD measurements. Moreover, our PR-MCD measurements show interesting feature of diluted magnetic semiconductor Ga1−xMnxAs of a high mole fraction x. PR-MCD signal persists in a reentrant insulating phase at temperatures blow half of Curie temperature (~80 K), and disappears right above it. Such an intrigue feature might be self-consistently explained by recent theory, developed for diluted magnetic semiconductors in the strong correlation regime.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2012