# Probing spinon nodal structures in three-dimensional Kitaev spin liquids

## TL;DR

This paper demonstrates that resonant inelastic X-ray scattering (RIXS) can effectively probe fractionalized excitations in 3D Kitaev spin liquids, revealing details about Majorana fermions and gauge fluxes.

## Contribution

It introduces the use of RIXS to distinguish Majorana fermion excitations and gauge fluxes in 3D Kitaev spin liquids, providing exact calculations for various lattice models.

## Key findings

- SC RIXS detects gapless Majorana fermions at Weyl points, nodal lines, or Fermi surfaces.
- Non-spin-conserving RIXS responses are dominated by gauge-flux excitations.
- SC RIXS response is suppressed around the $\Gamma$ point due to symmetry fractionalization.

## Abstract

We propose that resonant inelastic X-ray scattering (RIXS) is an effective probe of the fractionalized excitations in three-dimensional (3D) Kitaev spin liquids. While the non-spin-conserving RIXS responses are dominated by the gauge-flux excitations and reproduce the inelastic-neutron-scattering response, the spin-conserving (SC) RIXS response picks up the Majorana-fermion excitations and detects whether they are gapless at Weyl points, nodal lines, or Fermi surfaces. As a signature of symmetry fractionalization, the SC RIXS response is suppressed around the $\Gamma$ point. On a technical level, we calculate the exact SC RIXS responses of the Kitaev models on the hyperhoneycomb, stripyhoneycomb, hyperhexagon, and hyperoctagon lattices, arguing that our main results also apply to generic 3D Kitaev spin liquids beyond these exactly solvable models.