Electron correlations in MnxGa1-xAs as seen by resonant electron spectroscopy and dynamical mean field theory
Electron correlations in MnxGa1-xAs as seen by resonant electron spectroscopy and dynamical mean field theory
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DOI：
10.1038/ncomms3645
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发表时间：
2013-10-01
影响因子：
16.6
通讯作者：
Eriksson, O.
中科院分区：
文献类型：
--
作者：
Di Marco, I.;Thunstrom, P.;Eriksson, O.
自从在掺锰砷化镓中发现铁磁性以来的二十年里，其起源仍然存在争议，其中许多疑问都与电子结构有关。在这里，我们报告了锰掺杂砷化镓的价电子能谱的实验和理论研究。实验数据是通过非共振和共振光发射数据之间的差异获得的。理论谱的计算采用局部密度近似中的密度泛函理论和动态平均场理论的结合，并使用精确对角化作为杂质求解器。人们发现理论可以准确地再现测量数据并说明相关效应的重要性。我们的结果表明，锰态在很宽的能量范围内延伸，包括价带顶部，并且没有杂质带从价带边缘分裂，而诱导空穴似乎主要位于锰杂质周围。
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.