【摘要】 采用密度泛函理论研究了空位和反位缺陷效应对四元Heusler合金CoFeTiSb电子结构的影响。结果表明,Vd_Co、Vd_Fe空位缺陷和Ti_Sb反位缺陷具有负的形成能,能保持85%以上的自旋极化率,在CoFeTiSb合金工业制备过程中自发形成几率较大;Vd_Ti、Vd_Sb空位缺陷和Fe_Co反位缺陷虽然费米面处自旋极化率为100%,仍保持半金属性,但正的形成能表明在制备过程中它们出现的几率较小。此外,Sb_Co、Sb_Fe、Sb_Ti、Co_Ti、Fe_Ti反位缺陷由于具有较大的形成能和半金属性破坏,自旋极化率不同程度降低。更多还原

【Abstract】 Density functional theory（DFT）calculations were employed to investigate the effect of vacancy and antisite defects on the electronic structure of quaternary Heusler alloy CoFeTiSb.We found that Vd_Co,Vd_Fevacancies as well as Ti_Sbantisite defects were more likely to spontaneously occur as they had negative formation energies,which could keep at least 85% of spin polarization values in CoFeTiSb alloy.The half-metallic character was maintained for Vd_Ti,Vd_Sbvacancies and Fe_Coantisite defects with 100%spin polarization at the Fermi level,and its positive values of formation energy suggested lower probabilities to occur during the growth of CoFeTiSb.Whereas,Sb_Co,Sb_Fe,Sb_Ti,Co_Ti,Fe_Tiantisite defects had relatively high formation energies,their half-metallic character vanished and the spin polarization value declined.更多还原