Phase-dependent charge and heat current in thermally biased short Josephson junctions formed at helical edge states

Abstract

We explore the phase-dependent charge and heat current in short Josephson junctions with two normal metal regions attached at opposite ends, formed at helical edge states of two-dimensional topological insulators (TIs). For all finite phases, an asymmetry appears around the zero energy in the transmission spectra except for Φ=nΦ0, where n is an half-integer and Φ0 is the flux quantum. The phase-induced asymmetry plays a key role in inducing charge and heat current through the thermally biased junction. However, the current amplitudes are sensitive to the size of the junction. We show that in short Josephson junction when subject to temperature gradient, the charge current shows an odd-symmetry in phase. It indicates that the phase-tunable asymmetry around the zeroenergy is not suffcient to induce dissipative thermoelectric current in the junction. This is in contrast to the behavior of long Josephson junction as shown in the literature. The phase-tunable heat currents are obtained whose amplitudes are sensitive to the phase difference, base temperature, and system size.

Quasiparticles-mediated thermal diode effect in Weyl Josephson junctions

“…Noteworthy to mention, usage of Weyl materials for our TDE is justified as it is proved to be potential host for both intrinsic and proximity-induced superconductivity in the literature [89,90,92,93,95,[97][98][99][100][101] and also from the perspective of the current development of the field of thermal transport in superconducting junctions [75][76][77][78][79][80][81][82][83][84][85][86][87]. We have theoretically shown the TDE in a minimal model of WJJ.…”

“…The concept of thermal diode was developed using 1D lattices, metal-dielectric interfaces, normal metal tunnel junction, quantum Hall conductor, WSM, normal metal/superconductor hybrid junction [69][70][71][72][73][74]. Study of the superconducting hybrid junctions in this context is interesting since there appear some recent works on the thermal current in superconducting junctions including JJs which show distinct and interesting properties [75][76][77][78][79][80][81][82][83][84][85][86][87]. It is very timely and relevant to ask: is it possible to find thermal diode effect (TDE) using JJ?…”