Vortical versus skyrmionic states in the topological phase of a twisted bilayer with $d$-wave superconducting pairing

TL;DR

This paper investigates the vortex and skyrmionic states in twisted bilayer superconductors with d-wave pairing, highlighting their role as signatures of topological superconductivity and analyzing their behavior under magnetic fields.

Contribution

It reveals the presence of two distinct skyrmionic states in twisted bilayer superconductors with d-wave pairing and details their experimental signatures and evolution with twist angle.

Findings

Emergence of skyrmionic states in topological phase

Vortex matter as a signature of topological superconductivity

Skyrmionic states evolve with twist angle

Abstract

It was recently shown that a chiral topological phase emerges from the coupling of two twisted monolayers of superconducting Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ for certain twist angles. In this work, we reveal the behavior of such twisted superconducting bilayers with $d_{x^2-y^2}$ pairing symmetry in presence of applied magnetic field. Specifically, we show that the emergent vortex matter can serve as smoking gun for detection of topological superconductivity in such bilayers. Moreover, we report two distinct skyrmionic states that characterize the chiral topological phase, and provide full account of their experimental signatures and their evolution with the twist angle.