双钙钛矿Sr2-xLaxCrReO6的电子结构和磁性

采用密度泛函理论(DFT)在广义梯度近似(GGA)下的平面波超软赝势法, 研究了Sr2-xLaxCrReO6(x=0, 0.25, 0.5, 1)的晶体结构、电子结构和磁性. 通过几何结构优化, 得到了材料的晶格常数、电子和自旋分布以及磁矩的大小. 分析了La电子掺杂对Sr2CrReO6材料结构的影响, 发现当La掺杂浓度较小(x<1)时, Sr2-xLaxCrReO6仍保持半金属特性, 但刚好在费米面以下自旋向上的电子密度逐渐增大, 自旋向下能带的带隙增加, 总磁矩减小; 当掺杂浓度较大(x=1)时, Sr2-xLaxCrReO6从具有亚铁磁半金属性转化为铁磁金属性.

Electronic Structure and Magnetism of Double Perovskite Sr2-ILaxCrReO6

The ultrasoft pseudopotential wave method with the generalized gradient approximation to the density functional theory was adopted to study the electronic structures and magnetism of Sr2-xLaxCrReO6 (x=0, 0.25, 0.5, 1). Through the geometry optimization of the Sr2-xLaxCrReO6 system, lattice parameters, electron-and spin-distributions, and magnetic moments were obtained. It was found that for low doping level (x<1), the spin-up electronic density just below the Fermi energy increases, the band gap between the valence and conductive bands in the down-spin channel was enlarged, and the magnetic moment decreased with the increasing of La-doped level; at a certain concentration of La atoms (x=1) the Sr2-xLaxCrReO6 changed fromhalf-metallic to metallic and fromferrimagnetic to ferromagnetic.