Electron correlations in MnxGa1–xAs as seen by resonant electron spectroscopy and dynamical mean field theory

Abstract

After two decades since the discovery of ferromagnetism in manganese-doped gallium arsenide, its origin is still debated, and many doubts are related to the electronic structure. Here we report an experimental and theoretical study of the valence electron spectrum of manganese-doped gallium arsenide. The experimental data are obtained through the differences between off-and on-resonance photo emission data. The theoretical spectrum is calculated by means of a combination of density-functional theory in the local density approximation and dynamical mean field theory, using exact diagonalization as impurity solver. Theory is found to accurately reproduce measured data and illustrates the importance of correlation effects. Our results demonstrate that the manganese states extend over a broad range of energy, including the top of the valence band, and that no impurity band splits-off from the valence band edge, whereas the induced holes seem located primarily around the manganese impurity.

A self-consistent, relativistic implementation of the LSDA+DMFT method

“…In order to understand these features, we performed additional LSDA + DMFT calculations [19] and corresponding concentration dependent angle integrated study. The exact diagonalisation self energy as shown in the right panel of Figure 9 has been calculated using the parameters described by DiMarco et al [87]. The overall agreement between the resonant photoemission data [87] and the LDA+DMFT density of states shown in the left panel of Figure 9 is very good.…”

“…The exact diagonalisation self energy as shown in the right panel of Figure 9 has been calculated using the parameters described by DiMarco et al [87]. The overall agreement between the resonant photoemission data [87] and the LDA+DMFT density of states shown in the left panel of Figure 9 is very good. The shift of the majority d-states of Mn to the lower binding energies at −3 and −5 eV is in agreement with previous LSDA + U calculations [88].…”

Ab-Initio Investigations of Magnetic Properties and Induced Half-Metallicity in Ga1−xMnxP (x = 0.03, 0.25, 0.5, and 0.75) Alloys

“…These promising materials represent potential candidates designated to be typical half-metallic ferromagnets with 100% spin polarization at the Fermi level and this behavior is related to the incorporation of a convenient doped atom. Furthermore, the semiconductors substituted by 3d transition metals (TMs) turn salient, owing to the feasibility of merging magnetism and semiconductor features [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]. The 3d-TM doped III-V compounds behave as III-V DMS, which captivated a tremendous amount of attention for a viable growth in efficient and miniaturized electronic devices [16].…”

On the nature of the Mn-related states in the band structure of (Ga,Mn)As alloys via probing the E1 and E1 + Δ1 optical transitions

“…[11][12][13] These results are consistent with the recent experiments of hard X-ray angle-resolved photoemission spectroscopy, 14 and the very recent studies of resonant photoemission spectroscopy supported by dynamical mean field theory. 15 Here, we investigated six (Ga,Mn)As layers, with the Mn content from 0% to 6% and 20 nm-300 nm thickness, grown by a low-temperature molecular-beam epitaxy (LT-MBE) technique at a temperature of 230 C on semiinsulating (001) GaAs substrates. Both the Mn compositions and the layer thicknesses were estimated during the growth by the reflection high-energy electron diffraction (RHEED) oscillatory amplitude analysis.…”