Calculation of the band structure and density of localized states of materials of the quasi-binary system Zn3As2–Mn3As2

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Investigations of materials of the quasi-binary system Zn3As2–Mn3As2 have been performed. We present band structure calculations of crystal structures of Zn3As2, Mn3As2 and ZnMn2As2 within the framework of the density functional theory (DFT) and DFT + U method. The calculations based on first-principles were made using plane waves normalized on pseudopotential with the Quantum Espresso software package. Was obtained, that fundamental gap for Mn3As2 and Zn3As2 is equal to the optical band gap, while the band gaps for ZnMn2As2 was closer. The calculation for Mn3As2 and ZnMn2As2 by method DFT + U were performed; in these cases, the fundamental band gaps are closer to the optical band gaps, respectively. Considering the series Zn3As2 → ZnMn2As2 → Mn3As2, an increase in the Fermi energy was observed: Ef = 7.5 → 8.98 → 12.04 eV. It was established that the band gap of ZnMn2As2 (Eg = 0.6 eV) is a direct band gap corresponding to the transition between points Γ→Γ of the Brillouin zone. The Eg value obtained by us is closely known from experiments on optical absorption and the study of the temperature dependence of resistivity with Eg values equal to 0.8 eV and 0.76 eV, respectively. For Mn3As2 and ZnMn2As2, splitting is observed in density of states (DOS) between spin up and spin down electrons.