1305.5204 (Leonid V. Pourovskii et al.)

Theoretical prediction and spectroscopic fingerprints of an orbital
transition in CeCu2Si2    [PDF]

Leonid V. Pourovskii, Philipp Hansmann, Michel Ferrero, Antoine Georges

We show that the heavy-fermion compound CeCu2Si2 undergoes a transition between two regimes dominated by different crystal-field states. At low pressure P and low temperature T the Ce 4f electron resides in the atomic crystal-field ground state, while at high P or T the electron occupancy and spectral weight is transferred to an excited crystal-field level that hybridizes more strongly with itinerant states. These findings result from first-principles dynamical-mean-field-theory calculations. We predict experimental signatures of this orbital transition in X-ray spectroscopy. The corresponding fluctuations may be responsible for the second high-pressure superconducting dome observed in this and similar materials.

View original: http://arxiv.org/abs/1305.5204