Strong modulation of electronic properties of monolayer MoTe2 using a ferroelectric LiNbO3(0001) substrate

Abstract

In this study, we used first-principles density functional theory (DFT) calculations to investigate the interface coupling mechanism of a MoTe₂/LiNbO₃(0001) heterostructure and the effect of the LiNbO₃(0001) surface on the electronic properties of the MoTe₂ overlayer. It was found that the interface coupling between monolayer MoTe₂ and the LiNbO₃(0001) surface is due to the so-called ionic–vdW interaction mechanism and that the interface charge transfer depends not only on the band alignment between the free-standing materials but also on the interface chemical environments. The interface charge transfer exhibits a strong dependence on the ferroelectric polarization direction. The MoTe₂ overlayer on the thermodynamically preferred LiNbO₃(0001) negative and positive surfaces is characterized by an electron depletion of 7.4 × 10¹² and 3.32 × 10¹³ e cm⁻², respectively, which results in a large band offset of 1.0 eV. This facilitates the fabrication of seamless homojunctions in monolayer MoTe₂ on the oppositely polarized LiNbO₃(0001) substrate. Furthermore, examination of the electronic properties of the ferroelectric–polarization–reversed MoTe₂/LiNbO₃(0001) hybrid system indicates a strong modulation of the transport properties of the MoTe₂ overlayer, which provides a new possibility for the exploration of MoTe₂-based ferroelectric field-effect transistors.