Magnetic phase transitions in the two-dimensional frustrated quantum antiferromagnet Cs2CuCl4

TL;DR

This study investigates magnetic phase transitions in the 2D frustrated quantum antiferromagnet Cs2CuCl4 through magnetization and heat measurements, revealing complex phases and quantum fluctuations at very low temperatures and high magnetic fields.

Contribution

It provides detailed experimental data on phase transitions and quantum fluctuations in Cs2CuCl4, a model 2D frustrated quantum antiferromagnet.

Findings

Identification of multiple intermediate-field ordered phases.

Observation of strong zero-point quantum fluctuations.

Agreement with high temperature series expansion calculations.

Abstract

We report magnetization and specific heat measurements in the 2D frustrated spin-1/2 Heisenberg antiferromagnet Cs2CuCl4 at temperatures down to 0.05 K and high magnetic fields up to 11.5 T applied along a, b and c-axes. The low-field susceptibility chi (T) M/B shows a broad maximum around 2.8 K characteristic of short-range antiferromagnetic correlations and the overall temperature dependence is well described by high temperature series expansion calculations for the partially frustrated triangular lattice with J=4.46 K and J'/J=1/3. At much lower temperatures (< 0.4 K) and in in-plane field (along b and c-axes) several new intermediate-field ordered phases are observed in-between the low-field incommensurate spiral and the high-field saturated ferromagnetic state. The ground state energy extracted from the magnetization curve shows strong zero-point quantum fluctuations in the ground state at low and intermediate fields.