Heat Flow and X-Ray Diffraction Study on the Phase Transitions in CsPbCl 3

On the basis of the heat flow and X-ray diffraction measurements over a wide temperature range as well as precise heat flow and X-ray diffraction measurements employing "mK-stabilized cell" at the 320 K transition, we propose a predominant phase transition series in CsPbCl 3 . Existence of this new phase transition series has been examined on mixed crystals CsPbCl 3(1 m x ) Br 3 x ( x = 0.01, 0.05) and CsPbBr 3 single crystal by the heat flow and X-ray diffraction measurements, focusing on the hump of the heat flow which were observed from 320 K transition to 265 K in CsPbCl 3 .