2025/08/11 by Xun, Yechen, Zhang, Rui-Xing
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2508.08357
Threading magnetic flux into topological phases can induce bound states that reveal intrinsic properties of the ground state. In a 3D ℤ2 topological insulator, a quantized π flux traps a pair of 1D helical modes, whereas a trivial insulator hosts none. In this work, we show that in the presence of even-fold rotation symmetry Cn, a 3D band insulator features a refined ℤ2 × ℤ2 classification of the flux response. Specifically, it can host two distinct types of helical flux-bound modes that are distinguished by their angular momentum. When both types of flux modes coexist, the system is not a strong topological insulator, but a Cn-protected topological crystalline insulator. Building on this result, we propose that flux-threaded nanowires of such topological phase provide a natural platform for realizing 1D crystalline topological superconductors with multiple Cn-protected Majorana modes.