Heterostructures of topological insulator Bi2Se3 on transition metal dichalcogenides (TMDCs) offer a new materials platform for studying novel quantum states by exploiting the interplay among topological orders, charge orders and magnetic orders. The diverse interface attributes, such as material combination, charge re-arrangement, defect and strain, can be utilized to manipulate the quantum properties of this class of materials. Recent experiments of Bi2Se3/NbSe2 heterostructures show signatures of strong Rashba band splitting due to the presence of a BiSe buffer layer, but the atomic level mechanism is not fully understood. We conduct first-principles studies of the Bi2Se3/BiSe/TMDC heterostructures with five different TMDC substrates (1T phase VSe2, MoSe2, TiSe2, and 2H phase NbSe2, MoSe2). We find significant charge transfer at both BiSe/TMDC and Bi2Se3/BiSe interfaces driven by the work function difference, which stabilizes the BiSe layer as an electron donor and creates interface dipole. The electric field of the interface dipole breaks the inversion symmetry in the Bi2Se3 layer, leading to the giant Rashba band splitting in two quintuple layers and the recovery of the Dirac point in three quintuple layers, with the latter otherwise only occurring in thicker samples with at least six Bi2Se3 quintuple layers. Besides, we find that strain can significantly affect the charge transfer at the interfaces. Our study presents a promising avenue for tuning topological properties in heterostructures of two-dimensional materials, with potential applications in quantum devices.
@article{arxiv.2312.05112,
title = {Manipulating Topological Properties in Bi$_2$Se$_3$/BiSe/TMDC Heterostructures with Interface Charge Transfer},
author = {Xuance Jiang and Turgut Yilmaz and Elio Vescovo and Deyu Lu},
journal= {arXiv preprint arXiv:2312.05112},
year = {2023}
}