Quantum charge pumping through resonant crossed Andreev reflection in a superconducting hybrid junction of silicene

Abstract

We theoretically investigate the phenomena of adiabatic quantum charge pumping through a normal-insulator-superconductor-insulator-normal (NISIN) setup of silicene within the scattering matrix formalism. Assuming thin barrier limit, we consider the strength of the two barriers (χ1 and χ2) as the two pumping parameters in the adiabatic regime. Within this geometry, we obtain crossed Andreev reflection (CAR) with probability unity in the χ1-χ2 plane without concomitant transmission or elastic cotunneling (CT). Tunability of the band gap at the Dirac point by applying an external electric field perpendicular to the silicene sheet and variation of the chemical potential at the normal silicene region, open up the possibility of achieving perfect either CAR or transmission process through our setup. This resonant behavior is periodic with the barrier strengths. We analyze the behavior of the pumped charge through the NISIN structure as a function of the pumping strength and angles of the incident electrons. We show that large (Q ∼ 2e) pumped charge can be obtained through our geometry when the pumping contour encloses either the CAR or transmission resonance in the pumping parameter space. We discuss possible experimental feasibility of our theoretical predictions.

Nonlocal Andreev entanglements and triplet correlations in graphene with spin-orbit coupling

“…As a consequence, one can imagine a heterostructure made of a single s-wave superconductor and multiple nonsuperconducting electrodes in which an electron and hole excitation from different electrodes are coupled by means of a nonlocal Andreev process [7,[10][11][12][13]. This idea has so far motivated numerous theoretical and experimental endeavours to explore this entangled state in various geometries and materials [12,[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Nonetheless, the nonlocal Andreev process is accompanied by an elastic cotunneling current that makes it practically difficult to detect unambiguously the signatures of nonlocal entangled state [10,11,[13][14][15][16][17].…”

Electrically controllable thermal transport in Josephson junctions based on buckled two-dimensional materials

“…In doing so, the quasiparticle scattering angles in the superconducting regions turn to θ L,R eq,hq ≃ 0 and the relevant scattering problems reduce into one-dimensional scenarios, as that have been implemented in a series of studies [11][12][13][14]22]. In this paper, we are not interested in the effects of the interfacial potential barriers on the thermal conductance and single out Z L = Z R = π for definiteness, since the influences of interfacial potential barriers on the superconducting coherent transport have been intensively investigated [14,27,55,58]. It is well known that the transmis- sion probability and resulting conductance periodically oscillate with respect to Z L,R without decaying profiles, this phenomenon is a typical hallmark of the momentumspin/pseudospin locking in Dirac materials.…”

“…In this paper, we take the superconducting regions to be heavily doped to satisfy the relation of µ S ≫ µ M , so that the leakage of Cooper pairs from the superconducting regions to the magnetic region can rationally be neglected [50][51][52][53][54][55][56][57][58]. In doing so, the superconducting gap can be effectively modeled by a step function, In the present work, we study the thermal transport properties by virtue of the scattering wave approach.…”

“…Moreover, recent efforts have predicted that the superconducting correlations can be induced in BT-DMs through the proximity effect [47][48][49][50]. This progress together with the unique buckled geometry render BT-DMs fertile playgrounds to explore the electrically tunable phase-coherent transport properties [51][52][53][54][55][56][57][58]. One of the most prominent examples is the occurrence of electrically controlled 0 − π phase transition in silicene-based Josephson junctions [52][53][54].…”

“…One of the most prominent examples is the occurrence of electrically controlled 0 − π phase transition in silicene-based Josephson junctions [52][53][54]. Additionally, recent advances have also revealed that both the local and nonlocal Andreev reflections in silicene-based superconducting hybrid structures can be regulated by a perpendicular electric field [50,[55][56][57]. However, up to now the effects of perpendicular electric field on the phase-coherent thermal transport have been scarcely studied in BTDMsbased Josephson junctions.…”