声子振动对硒硫化钼/碲硒化钨异质双层电子结构影响的理论研究

Theoretical study of the influence of phonon vibration on electronic structures in MoSeS/WTeSe heterobilayers

文章以硒硫化钼/碲硒化钨异质双层结构为研究对象,采用基于密度泛函理论(density functional theory,DFT)的第一性原理计算方法,研究界面堆叠形式对体系电子结构的影响。结果表明:4种不同堆叠构型均表现出Ⅱ型能带对齐关系,但具有不同的层间带隙;计算能量最稳定的Te-Se构型的振动结构,发现平面和垂直声子模式的振动分布均表现出高度的空间局域特性;进一步研究频率为425、339、225、204 cm的声子模式对Te-Se构型电子结构的影响,表明激发垂直声子振动能引起界面距离、层内带隙及跃迁偶极矩的显著变化,而且该变化与电子态和声子振动的空间局域性密切相关。研究结果深化了声子振动对过渡金属硫族化合物异质层电子结构影响的认识,为利用声子调控光催化性能提供了理论支撑。

In this paper,by using first-principles calculations based on density functional theory(DFT),the vibrational and electronic structures were calculated together with the evolution of electronic structures with phonon vibrations for MoSeS/WTeSe heterobilayers.The calculation results show that,firstly,the heterobilayers with the four different stacking configurations all possess type-Ⅱband alignment but have the different interlayer band gaps.Secondly,the vibrational structures of Te-Se configuration with the most stable energy were calculated,and the in-plane and out-of-plane phonon vibrations are found to show highly spatial localization.Finally,the influences of the four phonon modes of 425,339,225 and 204 cmon the electronic structures of Te-Se configuration were investigated in details.The results show that the out-of-plane phonon vibrations can induce essential changes in interfacial distances,intralayer band gaps and transition dipole moments,and these changes are closely related to the spatial localization of electronic and phonon states.The results deepen the understanding of the influences of phonon vibration on electronic structures,and provide theoretical guide for regulating the phototransformation efficiency of TMDs heterobilayers.