ELECTRONIC STRUCTURE AND THE HALF-METALLIC FERROMAGNETIC BEHAVIOR OF THE Ti-DOPED BN SYSTEM STUDIED USING FIRST-PRINCIPLES

Abstract

In this work using the first-principles in the framework of Density Functional Theory the structural properties, electronic structure and  magnetism  of  Ti-doped  w-BN  are  studied.  Our  calculations  were  performed  with  the  ultrasoft pseudopotentials  method,  employed  exactly  as  implemented  in  Quantum  ESPRESSO  code.  For  the  B0.9375Ti0.0625N  and B0.875Ti0.125N concentrations it is found a ferromagnetic and half-metallic behavior with 100% carrier spin polarization of the  conduction  carriers  in  the  ground  state.  The  calculations  showed  that  the  substitution  of  a  Ti  atom  at  the  B  site (B0.9375Ti0.0625N  compound)  introduces  a  magnetic  moment  of  1.0  μB,  while  two  Ti  atoms  substitutions  (B0.875Ti0.125N compound) introduce a magnetic moment of 2.0 μB. These magnetic properties come from hybridization and polarization of states Ti-3d and their first neighboring B-2p and first neighboring N-2p atoms. Calculated magnetic properties indicate that Ti-doped w-BN compound can potentially be used in diluted magnetic semiconductors or as spin injectors.