Revisiting the Structural, Electronic, and Magnetic Properties of (LaO)MnAs: Effect of Hubbard Correction and Origin of Mott-Insulating Behavior

Abstract

We study the structural, electronic, and magnetic properties of the antiferromagnetic-layered oxyarsenide (LaO)­MnAs system from the first-principle calculation. The increasing Hubbard energy (U) in the Mn 3d orbital induces the increasing local-symmetry distortions (LSDs) in MnAs4 and OLa4 tetrahedra. The LSD in MnAs4 tetrahedra is possibly promoted by the second-order Jahn–Teller effect in the Mn 3d orbital. Furthermore, the increasing U also escalates the bandgap (E g) and the magnetic moment of Mn (μMn). The value of U = 1 eV is the most appropriate by considering the structural properties. This value leads to E g and μMn of 0.834 eV and 4.31 μB, respectively. The calculated μMn is lower than the theoretical value for the high-spin state of Mn 3d (5 μB) due to the hybridization between Mn 3d and As 4p states. However, d xy states are localized and show the weakest hybridization with valence As 4p states. The Mott-insulating behavior in the system is characterized by the E g transition between the valence and conduction d zx /d zy states. This work shows new physical insights for advanced functional device applications, such as spintronics.

Strongly bound Wannier–Mott exciton in pristine (LaO)MnAs and origin of ferrimagnetism in F-doped (LaO)MnAs

“…Our recent findings suggest that the G-type antiferromagnetic behavior of pristine (LaO)MnAs originated from the superexchange mechanism of MnAs 4 tetrahedra. 21 This research suggests that the superexchange mechanism dominates in the low doping concentration, while high doping concentration (25%) is dominated by Stoner exchange-dominated ferromagnetic (FM) ordering.…”

“…This result shows not much difference from the previous calculation (0.834 eV from Γ to M) with the same U value. 21 …”

“…We use the on-site Coulomb repulsion energy ( U ) 25 in the Mn 3d orbital with U = 1 eV, which is the most appropriate value considering the structural properties. 21 For band calculation, we calculated within a k -point path of M – A – Z – Γ – X – M – Γ in the corresponding Brillouin zone, as in our previous work. 21 Non-self-consistent-field (NSCF) calculation was performed to generate a spin-polarized total and projected DOS using the double k -point mesh of 16 × 16 × 8 ( x = 0) and 10 × 10 × 8 ( x = 0.0625, 0.125 and 0.25).…”

“… 21 For band calculation, we calculated within a k -point path of M – A – Z – Γ – X – M – Γ in the corresponding Brillouin zone, as in our previous work. 21 Non-self-consistent-field (NSCF) calculation was performed to generate a spin-polarized total and projected DOS using the double k -point mesh of 16 × 16 × 8 ( x = 0) and 10 × 10 × 8 ( x = 0.0625, 0.125 and 0.25). The calculations of the dielectric tensor were carried out using density functional perturbation theory (DFPT) within random phase approximation (RPA) and independent particle approximation (IPA).…”

“…Increasing U induces increased local-symmetry distortions in MnAs 4 and OLa 4 . 21 In this paper, we study the structural, electronic, magnetic, and optical properties of layered manganese-based (LaO)MnAs, with doping F − ions at the O 2− site. This system was calculated by rst principles based on the density functional theory (DFT).…”