Impurity-induced bound states in superconductors with topological order

Abstract

The study of classical spins in topological insulators [Phys. Rev. B {\bf 80}, 115216 (2009)] is generalized to topological superconductors. Based on the characteristic features of the so-called $F$-function, Bogoliubov-de Gennes Hamiltonian for superconductors is classified to positive, negative, and zero "gap" categories for topologically trivial and nontrivial phases of a topological superconductor as well as a BCS superconductor respectively. It is found that the $F$-function determines directly the presence or absence of localized excited states, induced by bulk classical spins and nonmagnetic impurities, in superconducting gap and their persistence with respect to impurity strength. Our results provide an alternative way to identify topologically insulating and superconducting phases in experiments while without resorting to the surface properties.

6 pages, 4 figures. More discussions and references are added. Accepted Accepted for publication in Journal of Physics: Condensed Matter

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Cited by in corpus (5)

• Shiba impurity bound states as a probe of topological superconductivity and Fermion parity changing quantum phase transitions
• Impurity bound states in fully gapped $d$-wave superconductors with subdominant order parameters
• Bound states around impurities in a superconducting bilayer
• Impurity-induced Mott ring states and Mott zeros ring states in the Hubbard operator formalism
• Chiral $p-$wave superconductivity in Pb${}_{1-x}$Sn${}_x$Te: signatures from bound-state spectra and wavefunctions