Pressure-induced Magnetic Quantum Phase Transition from Gapped Ground State in TlCuCl₃

Abstract

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