Diffuse Neutron and X-ray Scattering from Cesium Lead Bromide*

Cesium lead bromide has attracted recent attention, along with other lead halide perovskites, due to its optoelectronic properties. It has been proposed that the long carrier life supporting these properties is due to local polar fluctuations. To investigate the short-range lattice distortions that such fluctuations would imply, diffuse neutron and x-ray scattering experiments were performed on single crystals of CsPbBr₃ across range of temperatures spanning two structural phase transitions. Significant diffuse scattering indicating short-range displacement correlations was found in all three structural phases. In particular, diffuse neutron scattering from CsPbBr₃ shows distinct elastic and inelastic features, distinguishing between static and dynamic forms of local displacement correlations.