Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 54: Focus Session: Frontiers of electronic structure theory IV (O, jointly with HL, TT)

HL 54.10: Talk

Wednesday, March 13, 2013, 13:00–13:15, H36

Bulk electronic structure of the diluted magnetic semiconductor GaMnAs through hard x-ray angle resolved photoemission — •Jan Minar¹, Igor diMarco², J. Braun¹, H. Ebert¹, A.X. Gray³, and Ch. Fadley³ — ¹University of Munich, Munich, Germany — ²University of Upsalla, Upsalla, Sweden — ³UC Davis, Davis, USA

A detailed understanding of the origin of the magnetism in diluted magnetic semiconductors is crucial to their development for applications. Using hard X-ray angle-resolved photoemission [1] at 3.2 keV, we investigate the bulk electronic structure of the prototypical diluted magnetic semiconductor GaMnAs, and the undoped reference system GaAs [2]. The fully self-consistent combination of LSDA and dynamical mean field theory (DMFT) [3,4] and its combination with the one-step model of photoemission has been used to explain the experimental findings. Distinct differences are found between angle-resolved, as well as angle-integrated, valence spectra of GaMnAs and GaAs, in good agreement with theory. In addition to the standard LSDA based calculations the LSDA+DMFT approach shows an important effect of electronic correlations on the states close to the Fermi level. The combination of LSDA+DMFT and corresponding the Monte-Carlo simulations indicates an origin of ferromagnetism in GaMnAs and provides us a rather unifying picture of this controversial material.

[1]A. Gray et al., J. Minar et al., Nat. mat. 10, 759 (2011) [2] A. Gray, J. Minar et al., Nat. mat. 11, 957 (2012) [3] J. Minar, J. Phys.: Cond. Mat. (Topical Review) 23, 253201 (2011)