Cu掺杂AlN的铁磁稳定性的第一性原理计算

Ferromagnetism and its Stability of Cu-doped AlN From First Principles

文章采用基于密度泛函理论的平面波超软赝势法,结合广义梯度近似计算了Cu掺杂AlN的晶格常数、能带结构、电子态密度、铁磁态和反铁磁态的总能量,并通过平均场近似的海森堡模型估算了居里温度Tc。结果表明,Cu掺杂体系的能带结构呈现半金属性,半金属能隙为0.442eV。铁磁性是Cu原子的3d态与其最近邻的N原子的2p态通过p-d杂化作用而稳定的。当两个Cu原子相距最远且自旋平行排列时,体系具有最低的能量,估算出此时的居里温度高于室温,因此Cu掺杂AlN有望作为稀磁半导体材料。

Using the ultrapseudopotential method of plane wave based on density functional theory（DFT）,the lattice constants,density of states,energy band structure and the relative energy of ferromagnetic and antiferromagnetic orderings were calculated and discussed in detail.At the same time,Curie temperature Tc of Cu-doped AlN crystal was estimated by using the mean-field approximation of Heisenberg model.The results revealed that band structure of Cu-doped AlN crystal shows half metallic behavior and half metallic energy band is 0.442eV.The ferromagnetism was stabilized due to the p-d hybridization between Cu3d and N2p states.Doping system with the largest distance between two Cu atoms spin-arranged in parallel has the lowest total energy.And Tc is estimated beyond room temperature.These results suggest that Cu-doped AlN crystal may present a promising dilute magnetic semiconductor.