Chiral-Flux-Phase-Based Topological Superconductivity in Kagome Systems with Mixed Edge Chiralities

Abstract

Recent studies have attracted intense attention on the quasi-2D kagome superconductors $A{\text{V}}_3{\text{Sb}}_5$ ($A=$ K, Rb, and Cs) where the unexpected chiral flux phase (CFP) associates with the spontaneous time-reversal symmetry breaking in charge density wave (CDW) states. Here, commencing from the 2-by-2 CDW phases, we bridge the gap between topological superconductivity (TSC) and time-reversal asymmetric CFP in kagome systems. Several chiral TSC states featuring distinct Chern numbers emerge for an s-wave or a d-wave superconducting pairing symmetry. Importantly, these CFP-based TSC phases possess unique gapless edge modes with mixed chiralities (i.e., both positive and negative chiralities), but with the net chiralities consistent with the Bogoliubov-de Gennes Chern numbers. We further study the transport properties of a two-terminal junction, using Chern insulator or normal metal leads via atomic Green's function method with Landauer-Büttiker formalism. In both cases, the normal electron tunneling and the crossed Andreev reflection oscillate as the chemical potential changes, but together contribute to plateau transmissions (1 and 3/2, respectively). These behaviors can be regarded as the signature of a topological superconductor hosting edge states with mixed chiralities.

6 pages, 4 figures

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Cited by in corpus (6)

• Altermagnetism Induced Topological Phase Transitions in Kane-Mele Model
• Impact of Charge Density Waves on Superconductivity and Topological Properties in AV${}_3$Sb${}_5$ Kagome Superconductors
• Majorana modes in trapped-ion system and their Floquet engineering
• Constraints on the orbital flux phase in $A$V${}_3$Sb${}_5$ from polar Kerr effect
• Majorana edge states in s-wave kagome superconductors with Rashba interaction
• Exotic Topological Phenomena in Chiral Superconducting States on Doped Quantum Spin Hall Insulators with Honeycomb Lattices