First-Principles Investigation on the Fully Compensated Ferrimagnetic Behavior in Ti_2NbSb and TiZrNbSb

The electronic structures of Ti_2NbSb with Hg_2CuTi structure and TiZrNbSb with LiMgPdSn structure are investigated using first-principles calculations.The results indicate that Ti_2NbSb is a fully compensated ferrimagnetic spin-gapless semiconductor with an energy gap of 0.13 e V,and TiZrNbSb is a half-metallic fully compensated ferrimagnet with a half-metallic gap of 0.17 e V.For Ti_2NbSb,the total energy of the Hg_2CuTi structure is0.62 e V/f.u.higher than that of the L2_(1) structure,which is the ground state,and for TiZrNbSb,the total energy of the structure considered in this work is only 0.15 e V/f.u.larger than that of the ground state.Thus both of them may be good candidates for spintronic applications.     

C掺杂Mn3Ge的电子结构和磁性

采用第一性原理计算方法研究C掺杂对Mn₃Ge的影响.对Mn_3-xGeC_x的晶体结构进行几何优化,发现C原子最稳定的掺杂位置在正八面体的中心位置.研究其电子结构和总磁矩随C掺杂量的变化,发现总磁矩随着C浓度的增加先减小后增大,其中Mn₃GeC_0.4总磁矩接近零,可以实现完全的磁性补偿.研究Mn₃GeC_0.4多层膜的磁性,给出总磁矩接近零的Mn₃GeC_0.4多层膜结构,为Mn₃Ge的实际应用提供参考.