11 research outputs found
Thermoelectrics Near the Mott Localization-Delocalization Transition
We give an overview on current status of the theoretical research on
Thermoelectricity for correlated materials. We derive the theoretical formulas
which become exact at low and high temperature and discuss the intermediate
temperature results. In particular, we show that within Dynamical Mean Field
Theory the low temperature sign of the thermopower is not necessary the same as
in LDA, and that significant non-universality is expected due to strong
correlations.Comment: appeared in "Properties and Applications of Thermoelectric
Materials", Edited by V. Zlatic and A.C. Hewson, Springe
Optimizing thermal transport in the Falicov-Kimball model: binary-alloy picture
We analyze the thermal transport properties of the Falicov-Kimball model
concentrating on locating regions of parameter space where the thermoelectric
figure-of-merit ZT is large. We focus on high temperature for power generation
applications and low temperature for cooling applications. We constrain the
static particles (ions) to have a fixed concentration, and vary the conduction
electron concentration as in the binary-alloy picture of the Falicov-Kimball
model. We find a large region of parameter space with ZT>1 at high temperature
and we find a small region of parameter space with ZT>1 at low temperature for
correlated systems, but we believe inclusion of the lattice thermal
conductivity will greatly reduce the low-temperature figure-of-merit.Comment: 13 pages, 14 figures, typeset with ReVTe
Stability of a metallic state in the two-orbital Hubbard model
Electron correlations in the two-orbital Hubbard model at half-filling are
investigated by combining dynamical mean field theory with the exact
diagonalization method. We systematically study how the interplay of the intra-
and inter-band Coulomb interactions, together with the Hund coupling, affects
the metal-insulator transition. It is found that if the intra- and inter-band
Coulomb interactions are nearly equal, the Fermi-liquid state is stabilized due
to orbital fluctuations up to fairly large interactions, while the system is
immediately driven to the Mott insulating phase away from this condition. The
effects of the isotropic and anisotropic Hund coupling are also addressed.Comment: 7 pages, 9 figure
Superconducting pairing of spin polarons in the t - J model
Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal