Gapless spinon excitations emerging from a multipolar transverse field in the triangular-lattice Ising antiferromagnet NaTmSe2

TL;DR

This study demonstrates that NaTmSe2 exhibits gapless spinon excitations arising from multipolar interactions in a transverse field Ising model, revealing complex magnetic states with potential quantum computing applications.

Contribution

It provides the first comprehensive experimental and theoretical analysis of NaTmSe2, showing coexistence of multipolar and dipolar states with gapless spinons in a frustrated magnet.

Findings

NaTmSe2 realizes the transverse field Ising model with specific exchange parameters.

The material exhibits a multipolar spin-polarized state coexisting with a dipolar spin-disordered state.

Gapless spinon excitations are mediated by multipolar moments in NaTmSe2.

Abstract

The triangular-lattice quantum Ising antiferromagnet is a promising platform for realizing Anderson's quantum spin liquid, though finding suitable materials to realize it remains a challenge. Here, we present a comprehensive study of NaTmSe2 using magnetization, specific heat, neutron scattering, and muon spin relaxation, combined with theoretical calculations. We demonstrate that NaTmSe2 realizes the transverse field Ising model and quantitatively determine its exchange parameters. Our results reveal a multipolar spin-polarized state coexisting with a dipolar spin-disordered state. These states feature gapless spinon excitations mediated by the multipolar moments. The study shows how multiple types of magnetism can emerge in distinct magnetic channels (dipolar and multipolar) within a single magnet, advancing our understanding of spin-frustrated Ising physics and opening pathways for different quantum computing applications.