Neutron scattering investigations ofα-uranium in the charge-density-wave state

Below 43 K, $\alpha$-uranium (the orthorhombic phase stable below 600°C) develops an incommensurate charge-density wave (CDW) that has a profound effect on almost all physical properties of this element. Previous work at Oak Ridge National Laboratory and the Institut Laue-Langevin has characterized the phonon dispersion curves and various properties of the periodic distortions of the atomic structure. In this paper we review some of these results and present new information giving further details of the CDW state, in particular the temperature and pressure dependence of both the elastic and inelastic (precursor phonon) scattering. Suggestions for new experiments, including those using other techniques, are presented.