Year: 2020
Type: preprint
Abstract: We propose a class of topological superconductivity in which the pairing order is $\mathbb{Z}_2$ topologically obstructed in a three-dimensional time-reversal invariant system. When two Fermi surfaces are related by time-reversal and mirror symmetries, such as those in a $\mathbb{Z}_2$ Dirac semimetal, the inter-Fermi-surface pairing in the weak-coupling regime inherits the band topological obstruction. As a result, the pairing order cannot be well-defined over the entire Fermi surface and forms a time-reversal invariant generalization of U($1$) monopole harmonic pairing. A tight-binding model of the $\mathbb{Z}_2$ topologically obstructed superconductor is constructed based on a doped $\mathbb{Z}_2$ Dirac semimetal and exhibits nodal pairings. At an open boundary, the system exhibits a time-reversal pair of topologically protected surface states.
Source: arXiv (Cornell University)
Authors: Sun, Canon, Li, Yi
Institution: Johns Hopkins University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1924876975, G3820934480, G7740575714
OpenAlex ID: W3132498335