过渡金属掺杂SnO_2的电子结构与磁性

采用密度泛函理论及赝势平面波方法,对未掺杂SnO_2以及过渡金属V、Cr、Mn掺杂SnO_2的超原胞体系进行了几何优化,计算了晶格常数、电子结构与磁学性质.结果表明,6.25%与12.5%两种掺杂浓度时,体系的电子自旋和磁学性质没有发生很大的变化;相对于未掺杂SnO_2,过渡金属掺杂后SnO_2中O原子有向过渡金属移动的趋势,并使得O与掺杂金属之间键长变短;在V和Cr掺杂后,SnO_2具有半金属性质,而Mn掺杂SnO_2没有发现上述性质.6.25%与12.5%的杂质浓度对自旋和磁矩影响不大,掺杂产生的磁矩主要来自于过渡金属3d电子态,且磁矩的大小与过渡金属的电子排布有关.V、Cr、Mn掺杂SnO_2后的总磁矩分别为0.94μ_B、2.0μ_B、3.00μ_B.磁矩主要来源于过渡金属3d轨道的自旋极化,当O原子出现负磁矩的时候,还有很小一部分磁矩来源于临近过渡金属的Sn原子.

Electronic Structure and Magnetism of Transition Metal Doped SnO_2

Based on density functional theory,the geometric structures of SnO2 and transition metal (M) V-,Cr-,and Mn-doped SnO2 were studied by an ultrasoft pseudopotential implemented in the plane wave method.The geometrical parameters,density of states,and magnetic properties were calculated.By comparing two kinds of dopants with concentrations of 6.25% or 12.5%,no significant changes were observed for the electronic and magnetic properties of these systems.The O atom tended to be attracted by the M and the bond di...