N. Cavadini, W. Henggeler, A. Furrer, K. Krämer, H. U. Güdel, H. Mutka, A. Wildes and P. Vorderwisch
Quantum magnetic phase transition: a top-down approach
ILL Annual Report 2000, 12-13 (2001)                 

Abstract:Quantum magnetism exhibits unique collective features, bearing no classical analogies. The unconventional magnetic excitations realised in S =1/2 copper insulators KCuCl₃ and TlCuCl₃ were investigated by inelastic neutron scattering. We identify in TlCuCl₃ a promising candidate for the microscopic study of a quantum phase transition, driven by zero-point spin fluctuations at the lowest temperature. Such novel studies often remained precluded to neutron scattering due to the lack of suitable samples. Nevertheless, they address some of the most fundamental and debated issues of condensed matter physics.