Field-induced jammed polyhex spin liquid in the honeycomb Ising antiferromagnet

TL;DR

This paper investigates the ground state properties of honeycomb Ising antiferromagnets under magnetic fields, revealing a jammed spin liquid phase with extensive degeneracy and controllable spin diffusion, potentially observable in real materials.

Contribution

It introduces a new jammed spin liquid phase in honeycomb Ising antiferromagnets and explores how quantum fluctuations influence ground state degeneracy.

Findings

Existence of extensive ground state degeneracy mapped to polyhex tilings.

Identification of a jammed spin liquid phase with no local zero modes.

Quantum fluctuations partially lift degeneracy, favoring non-periodic tilings.

Abstract

We analyze the ground state properties of the honeycomb Ising antiferromagnet in an external magnetic field. We demonstrate the existence of extensive ground state degeneracy at finite field that maps to a polyhex tiling problem. This state is shown to be a jammed spin liquid, with no local zero modes connecting ground states. Through Monte Carlo simulations, we explore the properties of these states and show that the spin diffusion can be controlled by the magnetic field strength. By considering quantum fluctuations, we demonstrate that transverse coupling partially lifts the ground state degeneracy, selecting an extensive subspace of non-periodic tilings of 12-hexes. We suggest that the jammed polyhex spin liquid phase exists in an experimentally realizable region of parameter space and may be present in the FePX$_3$ compounds.