A Green’s function model for ferromagnetism and spin excitations of (Ga, Mn)As diluted magnetic semiconductors  

作　　者：刘贵斌 刘邦贵 

机构地区：[1]Institute of Physics,Chinese Academy of Sciences [2]Beijing National Laboratory for Condensed Matter Physics

出　　处：《Chinese Physics B》2009年第11期5047-5054,共8页中国物理B（英文版）

基　　金：Project supported by the National Nature Science Foundation of China (Grant Nos 10774180, 90406010 and 6062109);Funds of the Chinese Academy of Sciences for Key Topics in Innovation Engineering (Grant No KJCX2.YW.W09-5);the National Basic Research Program of China (Grant No 2005CB623602)

摘　　要：We study （Ga, Mn）As diluted magnetic semiconductors in terms of the Ruderman-Kittel-Kasuya-Yosida quantum spin model in Green＇s function approach. Random distributions of the magnetic atoms are treated by using an analytical average of magnetic configurations. Average magnetic moments and spin excitation spectra as functions of temperature can be obtained by solving self-consistent equations, and the Curie temperature TC is given explicitly. Tc is proportional to magnetic atomic concentration, and there exists a maximum for Tc as a function of carrier concentration. Applied to （Ga, Mn）As, the theoretical results are consistent with experiment and the experimental TC can be obtained with reasonable parameters. This modelling can also be applied to other diluted magnetic semiconductors.We study （Ga, Mn）As diluted magnetic semiconductors in terms of the Ruderman-Kittel-Kasuya-Yosida quantum spin model in Green＇s function approach. Random distributions of the magnetic atoms are treated by using an analytical average of magnetic configurations. Average magnetic moments and spin excitation spectra as functions of temperature can be obtained by solving self-consistent equations, and the Curie temperature TC is given explicitly. Tc is proportional to magnetic atomic concentration, and there exists a maximum for Tc as a function of carrier concentration. Applied to （Ga, Mn）As, the theoretical results are consistent with experiment and the experimental TC can be obtained with reasonable parameters. This modelling can also be applied to other diluted magnetic semiconductors.

关 键 词：diluted magnetic semiconductor Green＇s function Ruderman-Kittel-Kasuya-Yosida 

分 类 号：O472.5[理学—半导体物理]