11,241 research outputs found
Comment on "Energies of the ground state and first excited in an exactly solvable pairing model"
We comment on a recent application of the RPA method and its extensions to
the case of the two-level pairing model by N. Dinh Dang [1].Comment: 5 pages, 1 figure, submitted to EPJ
Covalency and the metal-insulator transition in titanate and vanadate perovskites
A combination of density functional and dynamical mean-field theory is
applied to the perovskites SrVO, LaTiO and LaVO. We show that
DFT+DMFT in conjunction with the standard fully localized-limit (FLL)
double-counting predicts that LaTiO and LaVO are metals even though
experimentally they are correlation-driven ("Mott") insulators. In addition,
the FLL double counting implies a splitting between oxygen and transition
metal levels which differs from experiment. Introducing into the theory an
\textit{ad hoc} double counting correction which reproduces the experimentally
measured insulating gap leads also to a - splitting consistent with
experiment if the on-site interaction is chosen in a relatively narrow
range ( eV). The results indicate that these early transition
metal oxides will serve as critical test for the formulation of a general
\textit{ab initio} theory of correlated electron metals.Comment: 5 pages, 3 figure
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