Pressure-Induced Magnetic Quantum Phase Transitions from Gapped Ground State in TlCuCl3

TL;DR

This study investigates how applying hydrostatic pressure to TlCuCl3 reduces its energy gap, leading to a quantum phase transition from a gapped state to antiferromagnetic order, with detailed measurements of magnetic properties.

Contribution

It provides the first detailed experimental analysis of pressure-induced quantum phase transitions in TlCuCl3, highlighting the gap closure and magnetic ordering behavior.

Findings

Gap closes at critical pressure Pc=0.42 kbar

Antiferromagnetic order appears beyond Pc

Spin-flop transition observed at 0.7T

Abstract

Magnetization maesurements under hydrostatic pressure were performed on an S=1/2 coupled spin system TlCuCl3 with a gapped ground state under magnetic field H parallel to the [2,0,1] direction. With increasing applied pressure P, the gap decreases and closes completely at Pc=0.42 kbar. For P>Pc, TlCuCl3 undergoes antiferromagnetic ordering. A spin-flop transition was observed at Hsf=0.7T. The spin-flop field is approximately independent of pressure, although the sublattice magnetization increases with pressure. The gap and Neel temperature are presented as function is attributed to to the relative enhancement of the interdimer exchange interactions compared with the intradimer exchange interaction.