Ferromagnetism in diluted magnetic semiconductors; Quantum Monte Carlo method with density functional theory

希薄磁性半導体における強磁性; 密度汎関数理論を用いた量子モンテカルロ法

Gu, B.; 大江 純一郎*; 前川 禎通

Gu, B.; Oe, Junichiro*; Maekawa, Sadamichi

The discovery of ferromagnetism in dilute magnetic semiconductor (DMS) has created much activity in the field of spintronics. The (Ga,Mn)As is regarded as a classic example with robust ferromagnetism coming from the partially filled d orbitals, while the highest reported Curie temperature is still well below room temperature. We develop a general combined numerical method for studying DMS, which can treat correlations correctly and that do not rely on arbitrary approximations or on the separation between charge, spin and orbital fluctuations. In this method, realistic parameters obtained by the ab initio calculations are used for performing quantum Monte Carlo calculations. We show that the proposed method well describes the magnetic properties of DMS and can be used for designing the new DMS materials which has high Curie temperatures.