3D Spin-orbital liquids

TL;DR

This paper explores exactly solvable three-dimensional spin-orbital models that host diverse gapless Majorana fermion phases, including topological metals, with analysis of their stability and phase transitions.

Contribution

It introduces a new class of 3D spin-orbital Hamiltonians based on Clifford algebras, revealing rich Majorana metal phases and their topological properties.

Findings

Discovery of gapless Majorana metals with Fermi surfaces, nodal lines, and Weyl points.

Identification of topological phase transitions driven by symmetry breaking.

Analysis of stability and splitting patterns of Majorana fermion structures.

Abstract

Spin-orbital liquids provide an exactly solvable route to three-dimensional Z2 quantum spin liquids beyond the original Kitaev setting. Built from higher-dimensional Clifford-algebra representations, spin-orbital Hamiltonians can be realized on both three- and four-coordinated lattices, giving rise to phases with 3 and 2 itinerant Majorana flavors. We demonstrate that these models host a rich set of gapless Majorana metals, characterized, in particular, by topological Fermi surfaces, nodal lines, and Weyl semimetal phases. We analyze the stability of these structures under physically motivated perturbations and identify generic splitting patterns and topological transitions driven by symmetry breaking and flavor mixing. This yields a unified organizing framework for three-dimensional Majorana metals in fractionalized spin liquids.