On edge states in superconductor with time inversion symmetry breaking

TL;DR

This paper explores how breaking time inversion symmetry in layered high-T_c superconductors affects their topological properties and boundary states, revealing that boundary currents are linked to topological invariants and fermion zero modes.

Contribution

It introduces the role of the topological invariant N in determining superconducting states with broken time inversion symmetry and analyzes boundary currents arising from topological differences.

Findings

Boundary currents depend on the difference in topological invariant N between domains.

Fermion zero modes at boundaries are proportional to 2(N_2 - N_1).

Topological properties influence superconducting boundary phenomena.

Abstract

Superconducting states with different internal topology are discussed for the layered high-T_c materials. If the time inversion symmetry is broken, the superconductivity is determined not only by the symmetry of the superconducting state, but also by the topology of the ground state. The latter is determined the integer-valued momentum-space topological invariant N. The current carrying boundary between domains with different N (N_2 and N_1) is considered. The current is produced by fermion zero modes, which number per one layer is 2(N_2-N_1).