First-principles Study Of Al_1-xCr_xN And Al_1-xV_xN Diluted Magnetic Semiconductors

Diluted magnetic semiconductors (DMS) have attracted wide interesting due to their potential exciting applications in modern micro-electronic industry. DMS are formed by incorporating the new spin degrees of freedom into traditional semiconductors, and may be made for entirely new electronic devices. Present experimental and theoretical studies mainly focus on: (1) The electronic structure and spin transport of DMS materials; (2) The origins of ferromagnetism in DMS materials; (3) The influence factors of DMS Curie temperature. A1N is a very wide band gap semiconductor, and AlN-based DMS have possible higher Curie temperature. Hence, AlN-based DMS may be an important spin-based electronic material. In this thesis, we investigate the ground state electronic structure and magnetic properties of Al_1-xCr_xN and Al_1-xV_xN systems using pseudopotential plane-wave method based on the density functional theory.Firstly, we optimize the lattice parameters of system and get the changed relation between lattice constants and concentrations of impurities. Meanwhile, we calculate the band structures and density of states in the ferromagnetic phase for x=0.03125 and x=0.0625, then analyze the electronic structure and magnetic properties.Secondly, we calculate the total energies of ferromagnetic and antiferromagnetic states by substituting Cr or V atoms for two Al atoms and obtain the doped...