| We only use the electron charge properties or spin characteristics in the traditionalelectronic devices, it is difficult to be fused to the same device, and spintronic deviceswill overcome this problem. Most of the research is diluted magnetic semiconductormaterials at present, and the spin polarization can be as high as100%, but the curietemperature of dilute magnetic semiconductor materials cannot reach to roomtemperature or fail to form a heterojunction in experiment, the dilute magneticsemiconductor is still at the experimental research stage and can not be applied to thespecific device. Although it is possible to reach above room temperature while Cr dopedwurtzite AlN or CaN, but it is easy to form the second phase and the doping atoms areeasy to gather, which lead to the source of diluted magnetic semiconductor magnetic isnot clear in theory. Yet nanoporous phase can overcome the above problem because ofits special structure. So this thesis studies the properties of transition metal dopednanoporous strcture of AlN in theoretically, We hope to give a better explain to themagnetic properties of the diluted magnetic semiconductor sources, but also providetheoretical guidance for experiments on the synthesis of new diluted magneticsemiconductor materials.In this thesis, we reasearched three aspects by using the first-principlespseudopotential method based on density functional, the generalized gradientapproximation (GGA) under the PBE functional.The first is the electronic structure andstability of the nanoporous structure,which is anew phase of AlN, the second is theimpacta of the transition metal V, Cr, Mn droped nanoporous structure of AlN withthe same concentration and the same location; The last is the magnetic and electriceffects on the nanoporous structure of AlN magnetoelectric properties with differentdoping concentration and different doping position by Cr atoms. The results show that:1) The stability of nanoporous structure of AlN is between Wurtzite AlN and rocksalt structure of AlN, The three structure can transform each other under certain pressureconditions. The nanoporous structure of AlN still a wide band gap semiconductor andthe band gap is2.671eV.2)The transition metal atom V, Cr, Mn atoms doped nanoporous structuralAl12N12will improve the conductive properties of the system, that is due to theimpurity band which is introduced by the of impurity atoms near the Fermi level. Band structure and density of states show that the Cr, Mn doped nanoporous structure AlNhave half-metallic characteristics, and the supercell half metal band gap are respectively0.495eV,0.028eV, but not V.3) The half-metallic energy gap will be changed when different concentration ordifferent position of Cr are doped in the nanoporous structure of AlN (221). Theconcentration of Cr is4.17%,8.33%,12.5%, and16.7%of the supercell half metal bandgap are respectively0.731eV,0.495eV,0.296eV and0.503eV, there are no obviouschange of regularity, but the concentration in a certain range of the band gap decreasewill increase the half-metallicity, but the concentration reduced will increase thehalf-metallic band gap in a certain range. In the Cr doped the nanoporous structure ofAlN with three kinds of different position and the same concentration,we found thecloser the distance between the doped atoms will lead to the half metallicity smaller. |
