Intertwining orbital current order and superconductivity in Kagome metal

TL;DR

This paper explores how orbital current order influences superconductivity in Kagome metals, revealing that different orbital current types lead to distinct unconventional superconducting states, with implications for experimental identification.

Contribution

The study derives a Landau-Ginzburg framework to classify orbital current and superconducting orders, highlighting their mutual influence and potential experimental signatures in Kagome metals.

Findings

Different orbital current orders induce distinct unconventional superconducting states.

Theoretical classification of possible orbital current and superconducting orders.

Proposed experiments to distinguish coexisting orbital current and superconducting states.

Abstract

The nature of superconductivity in newly discovered Kagome materials, $\text{AV}_3\text{Sb}_5$ (A=K, Rb, Cs), has been a subject of intense debate. Recent experiments suggest the presence of orbital current order on top of the charge density wave (CDW) and superconductivity. Since the orbital current order breaks time-reversal symmetry, it may fundamentally affect possible superconducting states. In this work, we investigate the mutual influence between the orbital current order and superconductivity in Kagome metal with characteristic van Hove singularity (vHS). By explicitly deriving the Landau-Ginzburg theory, we classify possible orbital current order and superconductivity. It turns out that distinct unconventional superconductivities are expected, depending on the orbital current ordering types. Thus, this information can be used to infer the superconducting order parameter when the orbital current order is identified and vice versa. We also discuss possible experiments that may distinguish such superconducting states coexisting with the orbital current order.