Mn掺杂ZnS(110)表面的电子结构和磁性

Structural,Electronic,and Magnetic Properties of Mn-doped ZnS(110) Surfaces:First-principles Study

采用基于密度泛函理论的第一性原理方法,研究Mn掺杂ZnS(110)表面的电子结构和磁性.计算分析不同掺杂组态的几何参数、形成能、磁矩、电子态密度以及电荷密度.结果表明:单个Mn原子掺杂,替位于表面第二层的Zn原子时体系形成能最低,说明该层是最稳定的掺杂位置.对于两个Mn原子的掺杂,当Mn与Mn之间呈反铁磁耦合时体系最稳定.体系的总磁矩和自由Mn原子的磁矩差别很小,但是Mn原子的局域磁矩却依赖于Mn原子的3d态和近邻S原子的3p态的杂化作用,即受周围S原子环境的变化影响较大.此外,分析电荷密度图得出Mn原子替换Zn原子后与S原子形成了更强的共价键.

Structural,electronic,and magnetic properties of Mn-doped ZnS（110） surfaces are investigated with first-principles method.Geometric parameters,formation energies,magnetic moments,density of states,and electron charge densities are studied.It shows that the lowest formation energy is as a Mn atom doped into the second layer,which indicates that this layer is more stable for Mn-doping.For bidoped case,the most stable configuration is an antiferromagnetic state of two Mn atoms.Total magnetic moments is equal to that of a free Mn atom.The local magnetic moment of Mn atom depends on a hybridization of Mn 3d state and its neighboring S 3p state,that is to say,magnetic moment changes as environment of S atoms alters.Furthermore,electron charge density shows that intensity of covalent bond between Mn and S atoms is greater than that between Zn and S atoms.