Signature of a randomness-driven spin-liquid state in a frustrated magnet

TL;DR

This study uncovers evidence of a disorder-driven spin-liquid state in a frustrated magnet, characterized by the absence of magnetic order down to very low temperatures and signatures of random-singlet formations.

Contribution

It provides experimental and theoretical evidence for a randomness-driven spin-liquid state in Li4CuTeO6, highlighting the role of disorder and quantum fluctuations in this material.

Findings

No long-range magnetic order down to 45 mK

Presence of random-singlet states inferred from scaling analyses

Consistent thermodynamic and muon spin relaxation results

Abstract

Collective behaviour of electrons, frustration induced quantum fluctuations and entanglement in quantum materials underlie some of the emergent quantum phenomena with exotic quasi-particle excitations that are highly relevant for technological applications. Herein, we present our thermodynamic and muon spin relaxation measurements, complemented by ab initio density functional theory and exact diagonalization results, on the recently synthesized frustrated antiferromagnet Li4CuTeO6, in which Cu2+ ions (S = 1/2) constitute disordered spin chains and ladders along the crystallographic [101] direction with weak random inter-chain couplings. Our thermodynamic experiments detect neither long-range magnetic ordering nor spin freezing down to 45 mK despite the presence of strong antiferromagnetic interaction between Cu2+ moments leading to a large effective Curie-Weiss temperature of -154 K. Muon spin relaxation results are consistent with thermodynamic results. The temperature and magnetic field scaling of magnetization and specific heat reveal a data collapse pointing towards the presence of random-singlets within a disorder-driven correlated and dynamic ground-state in this frustrated antiferromagnet.