Recent progress on magnetic-field studies on quantum-spin-liquid candidates

TL;DR

This review summarizes recent experimental progress in studying quantum spin liquid candidates under magnetic fields, focusing on geometrically frustrated systems and the Kitaev material alpha-RuCl3, highlighting evidence for and against QSL ground states.

Contribution

It provides a comprehensive overview of recent experimental findings on QSL candidates, emphasizing the progress and challenges in identifying QSL states.

Findings

Experimental progress has accelerated in recent years.

Evidence both supports and challenges the QSL ground state in studied materials.

Alpha-RuCl3 remains a key focus with ongoing debates about its QSL nature.

Abstract

Quantum spin liquids (QSLs) represent a novel state of matter in which quantum fluctuations prevent conventional magnetic order from being established, and the spins remain disordered even at zero temperature. There have been many theoretical developments proposing various QSL states. On the other hand, experimental movement was relatively slow largely due to limitations on the candidate materials and difficulties in the measurements. In recent years, the experimental progress has been accelerated. In this topical review, we give a brief summary of experiments on the QSL candidates under magnetic fields. We arrange our discussions by two categories: i) Geometrically-frustrated systems, including triangular-lattice compounds YbMgGaO4 and YbZnGaO4, kappa-(BEDT-TTF)2Cu2(CN)3, and EtMe3Sb[Pd(dmit)2]2, and kagome system ZnCu3(OH)6Cl2; ii) the Kitaev material alpha-RuCl3. Among these, we will pay special attention to alpha-RuCl3, which has been intensively studied by our and other groups recently. We will present evidence that both supports and unsupports the QSL ground state for these materials, based on which we give several perspectives to stimulate further research activities.