Ab-initio Computational Modeling Of Complex Magnetism In Spintronic Materials

摘要

In this paper, we present the results of density functional based first-principles electronic structure calculations for diluted magnetic semiconductors (DMS) used in semiconductor spintron-ics. We show that due to disorder, short ranged interactions and low concentration of dopants, magnetic percolation plays an important role in determining the Curie temperature, Using our calculated first principles parameters in Monte-Carlo simulations (MCS), we demonstrate this for Mn doped NiTiSn Heusler alloy. We also show how defects affect the properties of DMS, e.g., Mn doped ZnO, It will be shown that one can have a sizable Curie temperature with a certain combination of defects. One of the main obstacles to obtain well characterized properties of DMS is the wide variation of sample quality obtained from different growth conditions,e,g,, in spinodal decomposition leading to an inhomogeneous system consisting of clusters of magnetic dopants. We will demonstrate this by MCS of the inhomogeneous growth in Mn doped GaAs.