Sc与C掺杂MgS电子结构与光学性质的第一性原理研究

本文基于密度泛函理论的第一性原理方法，对Sc、C单掺以及共掺MgS体系的稳定性、电子结构和光学性质进行了研究，结果表明：与本征MgS体系相比，掺杂后体系的结合能仍为负值，表明掺杂体系均处于稳定状态，其中Sc-C共掺MgS体系的结合能最小，说明Sc-C共掺体系最稳定。掺杂后体系的禁带宽度均减小，表明电子由价带跃迁至导带的能量减小；此外，掺杂体系在低能区均发生了明显的红移现象，表明Sc、C掺杂能够有效的拓宽体系对可见光的响应范围。其中，Sc-C-MgS体系在费米能级附近产生了杂质能级且带隙宽度较小，在可见光范围内的吸收系数最优，可推测Sc-C共掺杂可作为提高MgS体系光催化活性的有效手段。

First-principles study on electronic structure and optical properties of Sc and C doped MgS

Based on the first principle method of density functional theory, this paper studies the stability, electronic structure, and optical properties of Sc, C single doped and co-doped MgS systems. The results show that compared with the intrinsic MgS system, the binding energy of the doped system is still negative, indicating that the doped systems are in a stable state. Among them, the binding energy of Sc-C co-doped MgS system is the smallest, indicating that Sc-C co-doped system is the most stable. After doping, the band gap width of the system decreases, indicating that the energy of electron transition from valence band to conduction band decreases; In addition, the doping system has an obvious red shift in the low-energy region, indicating that Sc and C doping can effectively broaden the response range of the system to visible light. Among them, Sc-C-MgS system produces impurity levels near the Fermi level, and the band gap width is small. The absorption coefficient is the best in the visible light range. It can be inferred that Sc-C co-doping can be used as an effective means to improve the photocatalytic activity of MgS system.