Large Tunable Thermophase in Superconductor -- Quantum Dot -- Superconductor Josephson Junctions

Abstract

In spite of extended efforts, detecting thermoelectric effects in superconductors have proven to be a challenging task, due to the inherent superconducting particle-hole symmetry. Here we present a theoretical study of an experimentally attainable Superconductor -- Quantum Dot -- Superconductor (SC-QD-SC) Josephson Junction with highly tunable thermoelectric properties and a thermal response that is far larger than previous suggestions. The QD energy level between the SCs breaks particle-hole symmetry in a gradual manner, allowing, in the presence of a temperature gradient, for gate controlled appearance of a superconducting thermo-phase. This thermo-phase increases up to a maximal value of $\pi /2$ after which thermovoltage is expected to develop. Using time-independent Keldysh countour Green's functions we derive the exact thermo-phase and thermal response on the junction. These are shown to be orders of magnitude larger than usual SC tunnel junctions with a sharp dependence on gate voltage.

Journal version - added interaction and discussion of HF validity

References in corpus (6)

• Supercurrent reversal in quantum dots
• Nanoscale phase-engineering of thermal transport with a Josephson heat modulator
• Perturbation theory of a superconducting $0-\pi$ impurity quantum phase transition
• Very large thermophase in ferromagnetic Josephson junctions
• Theory of a large thermoeffect in superconductors doped with magnetic impurities
• Resolving thermoelectric paradox in superconductors

Cited by in corpus (9)

• Towards phase-coherent caloritronics in superconducting circuits
• Bipolar Thermoelectric Josephson Engine
• Spin-dependent thermoelectric phenomena in a quantum dot attached to ferromagnetic and superconducting electrodes
• Phase-dependent heat and charge transport through superconductor-quantum dot hybrids
• Non-equilibrium thermoelectric transport across normal metal-Quantum dot-Superconductor hybrid system within the Coulomb blockade regime
• Phase and Thermal Driven Transport across T-Shaped Double Quantum Dot Josephson Junction
• Keldysh field theory approach to direct electric and thermoelectric currents in quantum dots coupled to superconducting leads
• Magnetic flux controlled current phase relationship in double Quantum Dot Josephson junction
• Quantum phase transition in a double quantum dot Josephson junction driven by electron-electron interactions