Persistent dynamics in the S=1/2 quasi-one-dimensional chain compound Rb4Cu(MoO4)3 probed with muon-spin relaxation

TL;DR

This study uses muon-spin relaxation to investigate the low-temperature magnetic dynamics of Rb4Cu(MoO4)3, revealing persistent spin excitations and ballistic transport indicative of a near-ideal one-dimensional quantum Heisenberg antiferromagnet.

Contribution

It provides detailed experimental evidence of persistent spin dynamics and ballistic transport in a quasi-one-dimensional antiferromagnetic chain compound.

Findings

No long-range magnetic order down to 50 mK

Dominance of ballistic spin transport below 0.3 K

Material is an excellent realization of a 1D quantum Heisenberg antiferromagnet

Abstract

We report the results of muon-spin relaxation measurements on the low-dimensional antiferromagnet Rb4Cu(MoO4)3. No long-range magnetic order is observed down to 50 mK implying a ratio T_N/J<0.005 (where J is the principal exchange strength along the spin chains) and an effective ratio of interchain to intrachain exchange of |J_perp/J|<2 x 10^-3, making the material an excellent realization of a one-dimensional quantum Heisenberg antiferromagnet. We probe the persistent spin excitations at low temperatures and find that ballistic spin transport dominates the excitations detected below 0.3 K.