Photoemission of Ga 1– x Mn x As with high Curie temperature and transformation into MnAs of zincblende structure

• Published in: physica status solidi (b) Vol. 246; no. 7; pp. 1435 - 1439
• Main Authors: Rader, O., Valencia, S., Gudat, W., Edmonds, K. W., Campion, R. P., Gallagher, B. L., Foxon, C. T., Emtsev, K. V., Seyller, Th
• Format: Journal Article
• Language: English
• Published: 01.07.2009
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200945209

Abstract Epitaxial films of Ga 1– x Mn x As, x = 0.08, with a high ferromagnetic ordering temperature ( T C = 160 K) grown and post‐growth annealed at low temperature (LT) have been studied in a photoemission experiment. The (100) surfaces were prepared by wet etching to remove surface segregated interstitials. By resonant photoemission at the Mn M‐edge, the appearence of a Mn induced main peak at 4.5 eV binding energy and an intense satellite at ∼7.2 eV are observed in full agreement with our previous work on Ga 1– x Mn x As with T C ∼50 K. Mn induced states are also observed around 1 eV to 2 eV but are of weaker intensity than in our previous work which may indicate a depletion of interstitial Mn. In no stage of surface preparation, emission from the gap region was observed where, according to recent local‐density calculations, interstitial Mn would contribute to the spectra. Additional annealing in situ changes the photoemission spectra strongly: The Mn 3d spectral weight increases altogether and the satellite decreases in intensity relative to the Mn 3d main peak and shifts to ∼6.5 eV. Comparison to the literature indicates that zincblende‐type MnAs is formed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)