Topology, interactions, & detection in superconductors

I

Multi-orbital magnetism & superconductivity

Iridates are an exciting family of materials that has turned out to be very similar to the well-known superconductors known as cuprates. These iridate compounds have an additional combination of promising properties, both strong spin-orbit coupling and strong coulomb interactions between electrons. This could result in unconventional types of superconductivity, even though none has been observed so far. This project aims to explore ways to find superconductivity in iridates.

PhysRevB.108.014508, PhysRevB.103.155147

II

Symmetry analysis of superconductivity

One of the key challenges in this field is to understand when unconventional symmetries of the superconducting order parameter are possible. In this project the focus is on finding methods or specific systems where additional constraint allows experiments to access more information about the symmetry of the order. This includes connecting orders to either spin- or pseudospin-fluctuations being dominant in a compound, as well as a formulation of a new effective model to explain the origin the critical field limit in a set of superconductors. This reveals that existing data rules out some theoretical options for the order. PhysRevB.108.014508, PhysRevB.111.134505

III

Accessing local topology

It has been predicted that there are superconducting orders that, even though the bulk is topologically trivial, can host non-abelian anyons due to the local non-trivial topology of the wavefunction. This project proposes a new type of experiments that can access the topological winding around nodes in a superconductor. Proof-of-concept is shown for one predicted topological nodal superconductor. The general technique formulated is however applicable for any 2D system with Dirac cones.

arXiv:2504.20775