286 research outputs found
Temperature Dependence of Thermopower in Strongly Correlated Multiorbital Systems
Temperature dependence of thermopower in the multiorbital Hubbard model is
studied by using the dynamical mean-field theory with the non-crossing
approximation impurity solver. It is found that the Coulomb interaction, the
Hund coupling, and the crystal filed splitting bring about non-monotonic
temperature dependence of the thermopower, including its sign reversal. The
implication of our theoretical results to some materials is discussed.Comment: 3 pages, 3 figure
Photo-induced insulator-metal transition of a spin-electron coupled system
The photo-induced metal-insulator transition is studied by the numerical
simulation of real-time quantum dynamics of a double-exchange model. The
spatial and temporal evolutions of the system during the transition have been
revealed including (i) the threshold behavior with respect to the intensity and
energy of light, (ii) multiplication of particle-hole (p-h) pairs by a p-h pair
of high energy, and (iii) the space-time pattern formation such as (a) the
stripe controlled by the polarization of light, (b) coexistence of metallic and
insulating domains, and (c) dynamical spontaneous symmetry-breaking associated
with the spin spiral formation imposed by the conservation of total spin for
small energy-dissipation rates
Towards precise measurement of oscillatory domain wall by ferromagnetic Josephson junction
We theoretically propose a principle for precise measurement of oscillatory
domain wall (DW) by a ferromagnetic Josephson junction, which is composed of a
ferromagnetic wire with DW and two superconducting electrodes. The
current-voltage curve exhibits stepwise structures, only when DW oscillates in
the ferromagnetic wire. The voltage step appears at V = n(\hbar/2e)\omega_DW
with the fundamental constant \hbar/e, integer number n, and the DW frequency
\omega_DW. Since V can be determined in the order of 10^9 accuracy, the
oscillatory DW will be measured more precisely than present status by
conventional method.Comment: 3 pages, 2 figure
Low energy electronic states and triplet pairing in layered cobaltates
The structure of the low-energy electronic states in layered cobaltates is
considered starting from the Mott insulating limit. We argue that the coherent
part of the wave-functions and the Fermi-surface topology at low doping are
strongly influenced by spin-orbit coupling of the correlated electrons on the
level. An effective t-J model based on mixed spin-orbital states is
radically different from that for the cuprates, and supports unconventional,
pseudospin-triplet pairing.Comment: 4 pages, 3 figure
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