Stability against contact interactions of a topological superconductor in two-dimensional space protected by time-reversal and reflection symmetries

Abstract

We study the stability of topological crystalline superconductors in the symmetry class DIIIR and in two-dimensional space when perturbed by quartic contact interactions. It is known that no less than eight copies of helical pairs of Majorana edge modes can be gapped out by an appropriate interaction without spontaneously breaking any one of the protecting symmetries. Hence, the noninteracting classification $\mathbb{Z}$ reduces to ${\mathbb{Z}}_8^{}$ when these interactions are present. It is also known that the stability when there are less than eight modes can be understood in terms of the presence of topological obstructions in the low-energy bosonic effective theories, which prevent opening of a gap. Here, we investigate the stability of the edge theories with four, two, and one edge modes, respectively. We give an analytical derivation of the topological term for the first case, because of which the edge theory remains gapless. For two edge modes, we employ bosonization methods to derive an effective bosonic action. When gapped, this bosonic theory is necessarily associated to the spontaneous symmetry breaking of either one of time-reversal or reflection symmetry whenever translation symmetry remains on the boundary. For one edge mode, stability is explicitly established in the Majorana representation of the edge theory.

16 pages with 1 figure

References in corpus (13)

• Topological Insulators with Inversion Symmetry
• Classification of topological insulators and superconductors in three spatial dimensions
• Topological Crystalline Insulators
• Reflection symmetric second-order topological insulators and superconductors
• The space group classification of topological band insulators
• Topology of crystalline insulators and superconductors
• Symmetry Protected Topological States of Interacting Fermions and Bosons
• Z2 topological term, the global anomaly, and the two-dimensional symplectic symmetry class of Anderson localization
• Topological zero modes and Dirac points protected by spatial symmetry and chiral symmetry
• Interaction effects on 1D fermionic symmetry protected topological phases
• Anderson localization and the topology of classifying spaces
• Bott periodicity for the topological classification of gapped states of matter with reflection symmetry
• Marginally localized edges of time-reversal symmetric topological superconductors

Cited by in corpus (2)

• Duality viewpoint of criticality
• Interacting Crystalline Topological Insulators in two-dimensions with Time-Reversal Symmetry