Hole sp3-character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches - newly found spin-unpolarized gap states of s-type below 1% of Mn

Abstract

The dilute magnetic semiconductor (Ga,Mn)As is ferromagnetic in accordance with the p-d Zener model. Hole density function (HDF) localization has been previously studied by means of the density functional theory (DFT) and non-standard DFT methods; however not for dopings near 1%. We have revised (Ga,Mn)As using the DFT with the pseudopotential self-interaction correction (pSIC) and maximally-localized Wannier functions (MLWFs), which show the sp3 character of a HDF. Nature of HDF is extended - for low dopings and the pSIC, 70% of the HDF is located within the inter-impurities region, and contribution of the 3d-Mn states is 3-5% for 1-3% of Mn with the pSIC, and 11% with the DFT. We found that for dopings below 1%, the spin-unpolarized s-type impurity states segregate from the conduction band to the energy gap - in contrast to earlier publications. This implies that donor co-doped dilute samples would be both insulating and nonmagnetic.

4 figures, 2 tables

References in corpus (5)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Maximally localized Wannier functions: Theory and applications
• On the character of states near the Fermi level in (Ga,Mn)As: impurity to valence band crossover
• Calculating dispersion interactions using maximally-localized Wannier functions
• Forces and atomic relaxations in the pSIC approach with ultrasoft pseudopotentials

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