Universal low-temperature properties of frustrated classical spin chain near the ferromagnet-helimagnet transition point

TL;DR

This paper investigates the universal low-temperature thermodynamic behavior of a classical frustrated spin chain near the ferromagnet-helimagnet transition, revealing critical phenomena and correlation changes at the Lifshitz point.

Contribution

It introduces a universal description of thermodynamics near the transition, linking classical and quantum models, and identifies the disappearance of helical correlations at a critical temperature.

Findings

Thermodynamic quantities are universal functions of temperature scaled by chiral domain wall energy.

Helical correlations vanish at a critical temperature, defining the Lifshitz point.

Susceptibility exhibits a maximum near the transition, consistent with experimental observations.

Abstract

The thermodynamics of the classical frustrated spin chain near the transition point between the ferromagnetic and the helical phases is studied. The calculation of the partition and spin correlation functions at low temperature limit is reduced to the quantum mechanical problem of a particle in potential well. It is shown that the thermodynamic quantities are universal functions of the temperature normalized by the chiral domain wall energy. The obtained behavior of the static structure factor indicates that the short-range helical-type correlations existing at low temperatures on the helical side of the transition point disappear at some critical temperature, defining the Lifshitz point. It is also shown that the low-temperature susceptibility in the helical phase near the transition point has a maximum at some temperature. Such behavior is in agreement with that observed in several materials described by the quantum $s=1/2$ version of this model.