Majorana multipole response: General theory and application to wallpaper groups

Article

关键词: TOPOLOGICAL INSULATORS;    ELECTROMAGNETIC PROPERTIES;    SYMMETRY;    SUPERCONDUCTIVITY;    SPECTROSCOPY;    CATALOG;    BANDS;   

DOI  :  10.1103/PhysRevB.103.224504

来源: SCIE

【 摘 要 】

Whereas identification of Cooper-pair symmetry is the first and crucial step in the investigation of unconventional superconductors, only a few have been established so far because of their own difficulties. To solve this problem, we develop a theory for identification of pairing symmetry using knowledge of topological superconductivity. Establishing the multipole theory of emergent Majorana fermions in time-reversal-invariant topological superconductors, we discover a one-to-one correspondence between the electromagnetic response of Majorana fermions and Cooper-pair symmetry. The emergent Majorana fermions host magnetic structures that share the same irreducible representation with Cooper pairs under crystalline symmetry. We furthermore reveal that Majorana fermions in high-spin or nonsymmorphic superconductors may exhibit magnetic octupole responses, which give a direct evidence of these exotic superconducting states. Electric responses of multiple Majorana Kramers pairs are also clarified. Our theory provides the fundamentals for identification of unconventional Cooper pairings through surface-spin-sensitive measurements as well as that for manipulation of Majorana fermions by external electromagnetic fields.

【 授权许可】

Free