Theoretical Aspects of the Charge Density Wave in Uranium

Using a first principles total energy method, we have reproduced the observed charge density wave (CDW) state of α-uranium (called α₁). This CDW is found to be a result of a Peierls-like transition, i.e., by opening of partial gaps at the Fermi level. The part of the Fermi surface affected by the distortion shows a strong nesting of fairly narrow f bands. In addition we suggest that the slightly modified α₁ CDW state, which is called α₂ and is observed by cooling the α₁ phase, is caused by a closely related mechanism, namely, by a nesting of the Fermi surface in the b direction. This is consistent with the observed CDW ordering.