Phase and Thermal-Driven Transport Across T-Shaped Double Quantum Dot Josephson Junction

KUMAR, BHUPENDRA; Verma, Sachin; Ajay, Ajay

doi:10.1007/s10948-023-06526-3

Cited by 5 publications

(17 citation statements)

References 61 publications

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“…Moreover, the sign of the TPSC is sensitive to the temperature [6]. In system of S-DQD-S, the magnitude of TPSC is adjustable with the help of the energy level of the side-coupled dot [8]. Whereas in the present S-MQD-S, our numerical results show that the sign of TPSC can be effectively reversed by variation of the direct MBS-MBS hybridization, QD-superconductor coupling in addition to the system temperature.…”

Section: Introductionmentioning

confidence: 69%

“…In analogous to the physical quantity of thermopower in NM-QD-NM that measures the induced bias voltage by temperature difference, the thermophase Seebeck coefficient (TPSC) in S-MQD-S is studied with particular attention paid on its sign change. Previous work showed that the magnitude of the TPSC in S-MQD-S depends on the dot level, coupling between the QD and superconductor leads, and system temperature [6,8]. Moreover, the sign of the TPSC is sensitive to the temperature [6].…”

Section: Introductionmentioning

confidence: 99%

“…In superconductor-based structures, the thermoelectric effect is further weakened by the dissipationless motion of Cooper pairs [3,4]. Therefore, only thermo-phase effects [4][5][6][7][8], which refers to the appearance of phase difference across a Josephson junction to completely cancel the thermocurrent, are usually observed in experiments. To improve the thermoelectric performance by breaking the particle-hole symmetry, particular device designation are required such as suppressing the Josephson coupling in superconducting tunnel junctions [4,5,9] or introducing other materials to form a superconducting hybridized system [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…Diverse superconducting hybridized structures were continuously proposed in the last two decades owing to the rapid development of nano-fabrication technologies [10,12]. One of them is the superconductor-quantum dot (QD)-superconductor (S-QD-S) device [6,8,10,[13][14][15][16][17][18]. The energy levels in QD are discrete and controllable with the help of external gate voltage or by changing the dot's size and host materials [19].…”

Section: Introductionmentioning

confidence: 99%

“…Transportation of quasi-particle and cooper pair in QD-based Josephson junctions has been investigated extensively both theoretically and experimentally in recent years. It was showed that the Josephson current through S-QD-S are well controlled [4][5][6]8,9]. On the other hand, much works were also devoted to phase-coherent thermal transport in superconductor-based circuits [20].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Thermophase Seebeck Coefficient in Hybridized Superconductor-Quantum-Dot-Superconductor Josephson Junction Side-Coupled to Majorana Nanowire

Gao,

Zhang,

et al. 2023

Nanomaterials

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The dc Josephson current is generated from phase difference between two superconductors separated by a mesoscopic thin film (Josephson junction) without external bias voltage. In the presence of a temperature gradient across the superconductors, a thermal phase is induced under the condition of open circuit. This is very similar to the Seebeck effect in the usual thermoelectric effect, and the thermal phase is thus named as thermophase Seebeck coefficient (TPSC). Here we find obvious enhancement and sign change of the TPSC unique to the Josephson junction composing of two superconductors connected to a semiconductor quantum dot (QD), which is additionally side-coupled to a nanowire hosting Majorana bound states (MBSs), the system denoted by S-MQD-S. These result arise from the newly developed states near the Fermi level of the superconductors due to the QD-MBS hybridization when the dot level is within the superconducting gap. The sign change of the TPSC provides a strong evidence of the existence of MBSs, and is absent if the QD is coupled to regular fermion, such as another QD (system denoted by S-DQD-S). We show that the magnitude and sign of the TPSC are sensitive to the physical quantities including interaction strength between the QD and MBSs, direct overlap between the MBSs, system equilibrium temperature, as well as hopping amplitude between the QD and the superconductors. The obtained results are explained with the help of the current-carrying density of the states (CCDOS), and may be useful in interdisciplinary research areas of Josephson and Majorana physics.

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Section: Introductionmentioning

confidence: 69%