Band structure engineering of van der Waals heterostructures using ferroelectric clamped sandwich structures
Hao Tian, Changsong Xu, Li Xu, Yurong Yang, L. Bellaïche, Di Wu
Abstract
A novel strategy of band structure engineering of van der Waals heterostructure is proposed using a ferroelectric (FE) clamped sandwich structure from first principles. The validity of the strategy is demonstrated in the sandwich structure of ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$/bilayer-${\mathrm{CrI}}_{3}/{\mathrm{In}}_{2}{\mathrm{Se}}_{3}$ (${\mathrm{In}}_{2}{\mathrm{Se}}_{3}/\mathrm{bi}\ensuremath{-}{\mathrm{CrI}}_{3}/{\mathrm{In}}_{2}{\mathrm{Se}}_{3}$) made by ferroelectric ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$ layers and semiconducting bilayer (SB) ${\mathrm{CrI}}_{3}$. Four states with different band structures in the FE/SB/FE sandwich structure are obtained by switching the FE polarization in the top and bottom ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$ layers. Two of the states possess spin-splitting semiconducting band structures with opposite spin channel in conduction bands which are generated from a spin-degenerated band structure of the ${\mathrm{CrI}}_{3}$ bilayer, resulting in an electric field controllable and nonvolatile four states spin-field effect transistor. The strategy of using FE layers to engineer band structures and generate spin-splitting semiconducting band structure in van der Waals heterostructure opens a new route in two-dimensional electronics and spintronics.