Predicted high ferromagnetic transition temperature and spin polarization of 3d orbitals in Cr- and Mn-doped AlP: First-principles study

Abstract

Transition-metal doping in semiconductors is a promising strategy to obtain magnetic and semiconducting properties in a single crystal and to enhance ferromagnetic (Fm) transition temperature (T C ) above room temperature, which is necessary for spintronic applications. It induces changes in bond lengths upon relaxation and introduces new electronic states in the band structure, which modify the band gap and potentially give rise to half-metallic behavior. To this end, density functional theory (DFT) calculations using the GGA-PBE functional, including Hubbard U corrections (PBE+ U) , were performed to investigate the electronic structure, magnetic properties, and orbital-resolved spin polarization of the dopant 3d states in Cr- and Mn-doped AlP compounds. The double substitution of Mn or Cr at next-nearest neighbor (NN) sites results in strong FM interactions, with an increased T C to 671 K for Mn and 897 K for Cr according to Hubbard U correction. Analyses of the band structure and projected density of states (PDOS) indicate that the NN configurations exhibit robust half-metallicity in both the PBE and PBE+ U calculations, with stronger spin polarization of the d-orbital components of the dopants under the U correction. These findings indicate that Cr- or Mn-doped AlP shows great promise for future spintronic applications.