Examining two-dimensional Fröhlich model and enhancing the electron mobility of monolayer InSe by dielectric engineering

In polar compounds, Fröhlich interaction plays an important role in electrical transport, and it is highly dependent on the dimensionality. In two-dimensional (2D) materials, Fröhlich interaction cannot be correctly described by the analytical model available for bulk materials, which prevents the employment of the state-of-the-art first-principles calculation of electrical transport based on maximally localized Wannier functions interpolation. Recently, an approximate 2D Fröhlich model with screened dielectric properties is proposed. Selecting the strong polar material of monolayer InSe, we examine the accuracy of this 2D Fröhlich model by comparing the electron mobility calculated using this model with that based on direct density functional perturbation theory calculations of 2D Fröhlich interaction. It is found that the 2D Fröhlich model can guarantee fairly good results with an advantage of tremendously reduced computational consumption. Using this model, the modulation of the electron mobility of monolayer InSe by the dielectric environment is studied. The electron mobility can be drastically enhanced by coating high-dielectric materials, with room-temperature mobility improved from about 100 c m 2 V − 1 s − 1 to about 500 c m 2 V − 1 s − 1, due to the strong suppression of Fröhlich scattering.