First-principles Study On Electronic Structure And Carrier Mobility Of Two-dimensional Materials ZrGeTe₄

Novel ternary layered transition metal dichalcogenides have gradually become the focus of two-dimensional materials research.In recent years,two-dimensional material ZrGeTe₄has attracted people's attention because of its strong anisotropy.In this paper,the electronic structure,phonon prop-erties and carrier mobility of layered ZrGeTe₄are studied by first-principles calculation.The research results are as follows:Firstly,by using the first-principles calculations with the hybrid Heyd-Scuseria-Ernzerhof?HSE?06 functional and considering the effect of spin–orbit coupling,the dependence of the layered ZrGeTe₄electronic structure on the number of layers is studied.The calculation results show that the band gap values of bulk and monolayer ZrGeTe₄are 0.55 eV and 1.08 eV,respectively.The band gap values cover the near-infrared region,and the monolayer Zr-GeTe₄has direct band gap,which indicates that it has potential applications in photovoltaic devices,solar cells and other fields.In addition,the potential physical mechanism of ZrGeTe₄band gap transition is explored by increasing the interlayer distance.The results show that when the interlayer distance increases to the critical value of 2.8?,the indirect band gap changes into a direct band gap,and the van der Waals interaction is the main reason for the band gap transition.Secondly,based on the density functional perturbation theory,by cal-culating the phonon spectrum of ZrGeTe₄,it is found that there is no virtual frequency in the phonon spectrum,which indicates that it has good mechan-ical stability.The simulated Raman spectrum is in good agreement with the experimental data,which shows that the parameters of phonon calculation are reasonable.Further analysis of phonon modes reveals the dependence of the phonon characteristics of ZrGeTe₄on the number of layers.Finally,using first-principles combined with deformation potential theo-ry to calculate,the dependence of the two-dimensional and three-dimensional ZrGeTe₄carrier mobility on the number of layers is studied.The calcula-tion results show that the electron mobility of ZrGeTe₄??10³cm²V-¹s-¹?is between graphene and MoS₂,and the carrier mobility exhibits strong anisotropy in the plane.The mobility in one direction is approximately 5–10times in the other direction.In addition,the relationship between ZrGeTe₄electron mobility with the number of layers is similar to the black phospho-rus,while the hole mobility changes with the number of layers.Based on the above research results,it is predicted that the two-dimensional material ZrGeTe₄will have a broad application prospect in optoelectronic devices,field-effect transistors and other fields.