Participants: Marco Casadei, Pierluigi Cudazzo, Matteo Gatti, Matteo Guzzo, Markus Holzmann, Federico Iori, Valerio Olevano, Eva Pavarini, John Rehr, Lucia Reining, Patrick Rinke, Pina Romaniello, Claudia Rödl, Francesco Sottile, Lorenzo Sponza, Martin Stankovski
DISCUSSION
MONDAY 5-12-2011
Eva Pavarini: Paramagnetism in Correlated Systems
Claudia Rödl: The Electronic Structure of CuO or the Problem of Symmetry
Patrick Rinke: H2 in RPA and GW
TUESDAY 6-12-2011:
Marco Casadei: Unraveling the α-γ phase transition in Cerium from first principle
The presence of localized, partially occupied f-electron states dictates many of the peculiar physical properties of rare-earth materials. In particular, the description of the isostructural α-γ phase transition in Cerium poses a great challenge to density-functional theory (DFT) based approaches since local/semilocal functionals (LDA/GGA) fail to produce the phase transition. We approach this problem by treating all electrons (including the f-electrons) at the same quantum mechanical level. The calculations are performed using both hybrid functionals (e.g. PBE0), that incorporate a portion of exact-exchange, and full exact-exchange plus correlation at the level of the random phase approximation (EX+cRPA). The PBE0 hybrid functional predicts the correct magnetic properties of both phases and yields a double minimum in the total energy versus volume curve, indicative of the phase transition, although with the wrong energetic order. EX+cRPA is then essential to capture the right energetic ordering of the minima. Our results suggest a hypothetical persistence of the phase transition to zero temperature, the driving mechanism being the change of the hopping amplitude between f-type orbitals.
Matteo Guzzo: Report on Graphite et al.
Lorenzo Sponza:Dynamical BSE
John Rehr: Phonon contributions to electron self-energy