Sliding ferroelectric controllable topological phases in the Bi2Te3/MnBi2Te4 heterobilayer

Sliding ferroelectricity and band topology are two fundamental phenomena in condensed matter physics that offer significant potential for both scientific exploration and technological applications. Here, based on first-principles, we show that the prototypical ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}/\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ heterobilayer supports the coexistence of sliding ferroelectricity and topological insulating states. Importantly, under appropriate external strain, the two nonequivalent ferroelectric (FE) states can exhibit distinct topological phases, enabling sliding FE control of the topological state. The explored findings not only provide foundations for exploring emergent phenomena and potential applications in ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}/\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ but also contribute to ongoing research on sliding ferroelectricity and topological insulating states at the heterointerfaces.