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Transport across junctions of pseudospin-one fermions

Nandy, Sourav and Sengupta, K and Sen, Diptiman (2019) Transport across junctions of pseudospin-one fermions. In: PHYSICAL REVIEW B, 100 (8).

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Official URL: https://dx.doi.org/10.1103/PhysRevB.100.085134

Abstract

We study transport across ballistic junctions of materials which host pseudospin-one fermions as emergent low-energy quasiparticles. The effective low-energy Hamiltonians of such fermions are described by integer spin Weyl models. We show that current conservation in such integer spin-s Weyl systems requires continuity across a boundary of only 2s (out of 2s + 1) components of the wave function. Using the current conservation conditions, we study the transport between normal metal-barrier-normal metal (NBN) and normal metal-barrier-superconductor (NBS) junctions of such systems in the presence of an applied voltage eV. We show that for a specific value of the barrier potential U-0, such NBN junctions act as perfect collimators; any quasiparticle which is incident on the barrier with a nonzero angle of incidence is reflected back with unit probability for any barrier width d. We discover an interesting symmetry of this system, namely, the conductance is invariant under U-0 -> 2(mu(L) +/- eV) - U-0, where mu(L) is the chemical potential and the +(-) sign corresponds to particle (hole) mediated transport. For NBS junctions with a proximity-induced s-wave pairing potential, which also display such a collimation, we chart out the properties of the subgap tunneling conductance G as a function of the barrier strength and applied voltage. We point out the effect of the collimation on the subgap tunneling conductance of these NBS junctions and discuss experiments which can test our theory.

Item Type: Journal Article
Additional Information: Copyright to this article belongs to AMER PHYSICAL SOC
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Depositing User: Id for Latest eprints
Date Deposited: 23 Sep 2019 09:57
Last Modified: 23 Sep 2019 09:57
URI: http://eprints.iisc.ac.in/id/eprint/63599

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