323,657 research outputs found
Seebeck coefficient of thermoelectric moleculat junction: First-principles calculations
A first-principles approach is presented for the thermoelectricity in
molecular junctions formed by a single molecule contact. The study investigates
the Seebeck coefficient considering the source-drain electrodes with distinct
temperatures and chemical potentials in a three-terminal geometry junction. We
compare the Seebeck coefficient in the amino-substituted and unsubstituted
butanethiol junction and observe interesting thermoelectric properties in the
amino-substituted junction. Due to the novel states around the Fermi levels
introduced by the amino-substitution, the Seebeck coefficient could be easily
modulated by using gate voltages and biases. When the temperature in one of the
electrodes is fixed, the Seebeck coefficient varies significantly with the
temperature in the other electrode, and such dependence could be modulated by
varying the gate voltages. As the biases increase, richer features in the
Seebeck coefficient are observed, which are closely related to the transmission
functions in the vicinity of the left and right Fermi levels.Comment: 4 pages; 2 figure
Large-N scaling behavior of the quantum fisher information in the Dicke model
Quantum Fisher information (QFI) of the reduced two-atom state is employed to
capture the quantum criticality of the superradiant phase transition in the
Dicke model in the infinite size and finite- systems respectively. The
analytical expression of the QFI of its ground state is evaluated explicitly.
And finite-size scaling analysis is performed with the large accessible system
size due to the effective bosonic coherent-state technique. We also investigate
the large-size scaling behavior of the scaled QFI of the reduced -atom state
and show the accurate exponent.Comment: 6pages,2figure
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