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Fermi level position, Coulomb gap, and Dresselhaus splitting in (Ga,Mn)As
- Source :
- Scientific Reports 6, 27266 (2016)
- Publication Year :
- 2016
-
Abstract
- Carrier-induced nature of ferromagnetism in a ferromagnetic semiconductor, (Ga,Mn)As, offers a great opportunity to observe novel spin-related phenomena as well as to demonstrate new functionalities of spintronic devices. Here, we report on low-temperature angle-resolved photoemission studies of the valence band in this model compound. By a direct determination of the distance of the split-off band to the Fermi energy EF, we conclude that EF is located within the heavy/light hole band. However, the bands are strongly perturbed by disorder and disorder-induced carrier correlations that lead to the Coulomb gap at EF, which we resolve experimentally in a series of samples, and show that its depth and width enlarge when the Curie temperature decreases. Furthermore, we have detected surprising linear magnetic dichroism in photoemission spectra of the split-off band. By a quantitative theoretical analysis we demonstrate that it arises from the Dresselhaus-type spin-orbit term in zinc-blende crystals. The spectroscopic access to the magnitude of such asymmetric part of spin-orbit coupling is worthwhile, as they account for spin-orbit torque in spintronic devices of ferromagnets without inversion symmetry.<br />Comment: 30 pages, 5 figures, supplemental info included
- Subjects :
- Condensed Matter - Materials Science
Subjects
Details
- Database :
- arXiv
- Journal :
- Scientific Reports 6, 27266 (2016)
- Publication Type :
- Report
- Accession number :
- edsarx.1606.02047
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1038/srep27266