Publication at Faculty of Mathematics and Physics |
2010
Abstract
Low-temperature specific heat experiments on Pu stabilized by Ce give the value of the Sommerfeld coefficient in the close vicinity of 40 mJ/mol K2. The most precise data set for Pu-6.1 at.% Ce yields = (41.5 and 0.5) mJ/mol K2 and the Debye temperature D = (103.0 and 0.5 K).
As Ce is in a compressed Ce state, major contribution to the value comes from the Pu states. Theoretical calculations suggest that the 5f 6 admixture in the 5f 5 ground state is responsible for the high value.
Although the 5f states are not present at the Fermi level, low-energy excitations due to transitions of the 5f 6 and 5f 5 type contribute to the spectral density around the Fermi level.