2,836 research outputs found
Interaction-tuned Anderson versus Mott localization
Disorder or sufficiently strong interactions can render a metallic state
unstable causing it to turn into an insulating one. Despite the fact that the
interplay of these two routes to a vanishing conductivity has been a central
research topic, a unifying picture has not emerged so far. Here, we establish
that the two-dimensional Falicov-Kimball model, one of the simplest lattice
models of strong electron correlation does allow for the study of this
interplay. In particular, we show that this model at particle-hole symmetry
possesses three distinct thermodynamic insulating phases and exhibits Anderson
localization. The previously reported metallic phase is identified as a
finite-size feature due to the presence of weak localization. We characterize
these phases by their electronic density of states, staggered occupation,
conductivity, and the generalized inverse participation ratio. The implications
of our findings for other strongly correlated systems are discussed.Comment: 5 pages, 4 figure
opendf - an implementation of the dual fermion method for strongly correlated systems
The dual fermion method is a multiscale approach for solving lattice problems
of interacting strongly correlated systems. In this paper, we present the
\texttt{opendf} code, an open-source implementation of the dual fermion method
applicable to fermionic single-orbital lattice models in dimensions
and . The method is built on a dynamical mean field starting point, which
neglects all local correlations, and perturbatively adds spatial correlations.
Our code is distributed as an open-source package under the GNU public license
version 2.Comment: 7 pages, 6 figures, 28th Annual CSP Workshop proceeding
High pressure effects in fluorinated HgBa2Ca2Cu3O(8+d)
We have measured the pressure sensitivity of Tc in fluorinated
HgBa2Ca2Cu3O(8+d) (Hg-1223) ceramic samples with different F contents, applying
pressures up to 30 GPa. We obtained that Tc increases with increasing pressure,
reaching different maximum values, depending on the F doping level, and
decreases for a further increase of pressure. A new high Tc record (166 K +/- 1
K) was achieved by applying pressure (23 GPa) in a fluorinated Hg-1223 sample
near the optimum doping level. Our results show that all our samples are at the
optimal doping, and that fluorine incorporation decreases the crystallographic
-parameter concomitantly increasing the maximum attainable Tc. This effect
reveals that the compression of the axes is one of the keys that controls
the Tc of high temperature superconductors.Comment: 4 pages, 4 figures, submitted to Phys. Rev.
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