Study on formation, electronic states evolution and spin polarization transition for MnGa compound under an anisotropic stress

Abstract

The Formations, stabilities, evolutions of geometries, electronic states together with the spin polarization transitions involved with magnetic properties of the MnGa compound under c axis anisotropic stress are systematically studied within the framework of density functional theory analyzing method. The results show that the anisotropically geometric expansion can be induced under stress. There are five kinds of atomic distances within the compound, with larger distance values for Mn–Mn and Ga–Ga, and smaller distances for Mn–Ga. The induced atomic distance fluctuations are also anisotropic, corresponding to the anisotropic binding strength regulations. The compound under stress is more stable. The s orbital releases electrons, the p and the d orbitals accept electrons for Mn. The s orbital and the d orbital release electrons, the p orbital traps electrons for Ga. The Mn1 and Mn2, Ga1 and Ga2 have diversified configurations under stress. A transition of ionic state of Mn2 is observed. Electrons transfers occur between orbitals and species under stress. The MnGa has anisotropic conductor band structure. The effective mass of conduction band as well as shallow valence band are enhanced under stress. The electronic band experiences a transition from semimetal into metal. The s, p and d electrons form the conduction band and shallow valence band. The d electrons mainly form the deep valence band, too. The localization at −16.8eV of d electrons is weakened under stress. The Mnd electrons get less responsible for the spin state under stress. The Mn1 and Mn2 turn to exhibiting distinctively diverse profiles, the Ga1 and Ga2 turn to exhibiting the same profiles under stress. The Mn shows strong atomic magnetic moment than that of Ga.