Effect of assisted hopping on thermopower in an interacting quantum dot

Abstract

We investigate the electrical conductance and thermopower of a quantum dot tunnel coupled to external leads described by an extension of the Anderson impurity model which takes into account the assisted hopping processes, i.e., the occupancy-dependence of the tunneling amplitudes. We provide analytical understanding based on scaling arguments and the Schrieffer-Wolff transformation, corroborated by detailed numerical calculations using the numerical renormalization group (NRG) method. The assisted hopping modifies the coupling to the two-particle state, which shifts the Kondo exchange coupling constant and exponentially reduces or enhances the Kondo temperature, breaks the particle-hole symmetry, and strongly affects the thermopower. We discuss the gate-voltage and temperature dependence of the transport properties in various regimes. For a particular value of the assisted hopping parameter we find peculiar discontinuous behaviour in the mixed-valence regime. Near this value, we find very high Seebeck coefficient. We show that, quite generally, the thermopower is a highly sensitive probe of assisted hopping and Kondo correlations.

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Cited by in corpus (14)

• Spin-resolved thermal signatures of Majorana-Kondo interplay in double quantum dots
• Heat current across a capacitively coupled double quantum dot for high magnetic field
• Local and non-local thermopowers in three-terminal nanostructures
• Fate of the spin-\frac{1}{2} Kondo effect in the presence of temperature gradients
• Interplay of the Kondo effect with the induced pairing in electronic and caloric properties of T-shaped double quantum dots
• Charge and heat transport through quantum dots with local and correlated-hopping interactions
• Spin Seebeck effect of correlated magnetic molecules
• Effect of correlated hopping on thermoelectric properties: Exact solutions for the Falicov-Kimball model
• Influence of assisted hopping interaction on the linear conductance of quantum dot
• Resonant enhancement of thermoelectric properties by correlated hopping for the Falicov-Kimball model on Bethe lattice
• Nonlocal correlations in the optical conductivity spectra
• Effects of correlated hopping on thermoelectric response of a quantum dot strongly coupled to ferromagnetic leads
• Thermoelectric properties of Mott insulator with correlated hopping at microdoping
• Signatures of the Correlated-Hopping Interaction in Non-Linear Transport through a Quantum Dot