Cr掺杂纤锌矿GaN的磁性和光学性质

Magnetic and optical properties of Cr-doped wurtzite GaN

采用自旋极化密度泛函理论方法,对Cr掺杂纤锌矿GaN的能带结构和态密度进行计算,通过计算的能带结构和光学线性响应函数,系统讨论了Cr掺杂对纤锌矿GaN电子结构、磁学和光学属性的影响。计算结果显示:Cr掺杂纤锌矿GaN的反铁磁态具有半金属特征,铁磁态具有金属特性和磁性,磁矩主要源于费米能级附近的Cr 3d和N 2p能带发生劈裂导致自旋向上和自旋向下的电子的态密度不同所致。光学性质计算结果显示,Cr掺杂纤锌矿GaN的费米能级附近出现极大的介电峰,具有优异的发光性能,峰值对应于紫外波段,在高能区吸收峰发生了红移现象,在低能区红外波吸收增强。理论计算表明,Cr掺杂纤锌矿GaN可能是一种性能优异的磁光材料。

Using the spin polarization density fimctional theory, the energy band structure and density of states of Cr-doped wurtzite GaN was caculated. By the calculation result of the energy band structure and optic linear response function, the effects of Cr-doping on electronic structure, magnetic and optical properties of wurtzit GaN were discussed. The calculation result shows that the anti-ferromagnetic state of Cr-doped WtLrtzite GaN has sernimetal characteristics; the ferromagnetic state has metallic and magnetic characteristics. The magnetic moments are mainly caused by the spin upward and spin downward electronics come from Cr 3d and N 2p energy band near the Fermi level, which occurs separation. Optics quality calculation shows that there is huge dielectric peak, which has excellent luminescence property, appeared around the Fermi level of Cr-doped wurtzite GaN. The peak is corresponding to ultraviolet band, occurs red shift in the high energy area of absorption peak. The infrared absorption enhances in the low energy region. The theoretical calculation results demonstrate that Cr-doped wurtzite GaN could be a kind of excellent magneto-optic material.