Excitations in Spin Chains and Specific-Heat Anomalies in Yb(4)As(3)

TL;DR

This paper explains the magnetic-field dependence of low-temperature specific heat in Yb(4)As(3) using a model of spin chains with weak inter-chain coupling, successfully reproducing experimental data.

Contribution

It introduces a model incorporating weak inter-chain magnetic coupling to explain specific-heat anomalies in Yb(4)As(3).

Findings

The model reproduces experimental specific heat data.

Inter-chain coupling ratio J'/J is about 10^{-4}.

Heavy-fermion behavior is explained by the spin chain model.

Abstract

An explanation is given for the observed magnetic-field dependence of the low-temperature specific heat coefficient of Yb(4)As(3). It is based on a recently developed model for that material which can explain the observed heavy-fermion behaviour. According to it the Yb(3+)-ions are positioned in a net of parallel chains with an effective spin coupling of the order of J = 25 K. The magnetic-field dependence can be understood by including a weak magnetic coupling J' between adjacent chains. The data require a ratio J'/J of about 10^{-4}. In that case the experimental results can be reproduced very well by the theory.