Neutron Scattering Study of Jahn-Teller Phase Transition in RbCuCl₃

Abstract

In this letter we report on a neutron scattering investigation of the cooperative Jahn-Teller phase transition in RbCuCl₃. We observed strong critical diffuse scattering due to correlated fluctuations of J–T clusters. This is in sharp contrast to the previously reported scattering characteristics of CsCuCl₃ which undergoes similar J–T phase transitions. In CsCuCl₃, no critical scattering was observed, however, strong Huang scattering around Bragg reflections was observed. These results indicate that the interactions which cause cooperative J–T phase transitions in these materials may be substantially different.