Impurity-induced excitations in a topological two-dimensional ferromagnet/superconductor van der Waals moiré heterostructure

Abstract

The emergence of a topological superconducting state in van der Waals heterostructures provides a new platform for exploring novel strategies to control topological superconductors. In particular, impurities in van der Waals heterostructures, generically featuring a moir\'e pattern, can potentially lead to the unique interplay between atomic and moir\'e length scales, a feature absent in generic topological superconductors. Here we address the impact of nonmagnetic impurities on a topological moir\'e superconductor, both in the weak and strong regime, considering both periodic arrays and single impurities in otherwise pristine infinite moir\'e systems. We demonstrate a fine interplay between impurity-induced modes and the moir\'e length, leading to radically different spectral and topological properties depending on the relative impurity location and moir\'e lengths. Our results highlight the key role of impurities in van der Waals heterostructures featuring moir\'e patterns, revealing the key interplay between length and energy scales in artificial moir\'e systems.