# Nontrivial Triplon Topology and Triplon Liquid in Kitaev-Heisenberg-type Excitonic Magnets

## TL;DR

This paper explores topological properties of triplon excitations in Kitaev-Heisenberg-type excitonic magnets, revealing nontrivial band topology and a novel triplon liquid phase in Mott insulators with strong spin-orbit coupling.

## Contribution

It introduces the concept of nontrivial triplon band topology and identifies a triplon liquid phase in Kitaev-Heisenberg-like excitonic magnets, expanding understanding of quantum magnetic states.

## Key findings

- Triplons acquire nontrivial band topology in a magnetic field.
- Identification of a triplon liquid phase analogous to Kitaev's spin liquid.
- Magnetic states include both ordered phases and a novel triplon liquid.

## Abstract

The combination of strong spin-orbit coupling and correlations, e.g. in ruthenates and iridates, has been proposed as a means to realize quantum materials with nontrivial topological properties. We discuss here Mott insulators where onsite spin-orbit coupling favors a local $J_{\textrm{tot}}=0$ singlet ground state. We investigate excitations into a low-lying triplet, triplons, and find them to acquire nontrivial band topology in a magnetic field. We also comment on magnetic states resulting from triplon condensation, where we find, in addition to the same ordered phases known from the $J_{\textrm{tot}}=\tfrac{1}{2}$ Kitaev-Heisenberg model, a triplon liquid taking the parameter space of Kitaev's spin liquid.