# Field-induced instability of the quantum-spin-liquid ground state in the $J_{\rm eff}=\frac{1}{2}$ triangular-lattice compound NaYbO$_2$

## TL;DR

This study investigates NaYbO$_2$, a triangular-lattice compound, revealing a spin-liquid ground state at zero field and a field-induced quantum phase transition to magnetic order above 2 T, using various bulk and local probes.

## Contribution

It provides experimental evidence of a field-induced quantum phase transition in a $J_{eff}=1/2$ triangular-lattice compound, expanding understanding of frustrated quantum magnetism.

## Key findings

- No long-range magnetic order down to 0.3 K at zero field
- Field-induced magnetic order observed above 2 T
- Persistent spin fluctuations at low fields

## Abstract

Polycrystalline samples of NaYbO$_2$ are investigated by bulk magnetization and specific-heat measurements, as well as by nuclear magnetic resonance (NMR) and electron spin resonance (ESR) as local probes. No signatures of long-range magnetic order are found down to 0.3~K, evidencing a highly frustrated spin-liquid-like ground state in zero field. Above 2\,T, signatures of magnetic order are observed in thermodynamic measurements, suggesting the possibility of a field-induced quantum phase transition. The $^{23}$Na NMR relaxation rates reveal the absence of magnetic order and persistent fluctuations down to 0.3~K at very low fields and confirm the bulk magnetic order above 2~T. The $H$-$T$ phase diagram is obtained and discussed along with the existing theoretical concepts for layered spin-$\frac{1}{2}$ triangular-lattice antiferromagnets