Diffuse-neutron-scattering investigation of the low-temperature phases of sodium

Abstract
The low-temperature phase of sodium is investigated by diffuse-neutron-scattering techniques. In contrast to previous results for lithium no disordered close-packed polytype stacking sequences were observed. The results show the presence of two long-range-ordered, but faulted hcp and 9R structures. The temperature behavior indicates a higher stability of cubic stacking faults at lower temperatures.