Exact first-principles calculation reveals universal moiré potential in twisted two-dimensional materials
Dong Liu, Jiang Zeng, Xingxing Jiang, Li‐Ming Tang, Ke‐Qiu Chen
Abstract
Recently, twisted moir\'e systems have attracted intense attention, where the emergence of the moir\'e potential is experimentally observed as an effective way to regulate the electron and exploit novel properties. Various theoretical models have been proposed and attributed the moir\'e potential as a result from interlayer electrical polarization or atomic relaxation effects. To date, the moir\'e potential is not yet directly calculated via an exact first-principles method and the universal mechanism in different systems is still unclear. Here, we obtain and analyze the surface superlattice potential by directly using first-principles calculations. We demonstrate that the moir\'e potential is a widely existing phenomenon in twisted systems with or without interlayer electrical polarization and is generally determined by the local work function. Specifically, the surface moir\'e potential is positively proportional to the local work function in single-atom-thick materials and negatively in multi-atom-thick ones due to a compensation effect. Interestingly, the surface potential amplitude of an unpolarized phosphorene system ($\ensuremath{\sim}430$ meV) is much larger than that of the polarized $h$-BN system ($\ensuremath{\sim}170$ meV). Our work directly reveals the universal moir\'e potential via fully first-principles calculations and provides a different angle in the study of moir\'e systems and twistronics.