Nonlocal transport in superconducting heterostructures based on Weyl semimetals

Li, Hai; Ouyang, Gang

doi:10.1103/physrevb.100.085410

Cited by 11 publications

(9 citation statements)

References 45 publications

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“…y , which is anisotropic in the momentum space. To address the effects of the intrinsic anisotropy on the subgap transport properties, we consider a SDM-based NS junction with the normal direction of NS interface defining as n = (cos θ, sin θ), where θ indicates the interface orientation angle between directions of the x-axis and n, as that carried out in the superconducting hybrids based on monolayer phosphorus [50] and type-II Weyl semimetals [16,17]. In this way, the NS interface is located at x = −y tan θ, as schematically shown in figure 1.…”

Section: Model and Methodsmentioning

confidence: 99%

“…In this regard, the influences of the interfacial barrier on the subgap transport are orientation-dependent, in stark contrast to that in superconducting hybrids based on type-II Weyl semimetals. In type-II-Weyl-semimetal-based superconducting hybrids, the differential conductance oscillates with the interfacial barrier strength without a decaying profile, although the low-energy excitations in type-II Weyl semimetals are also anisotropic due to the tilting of Weyl cones [17]. The anisotropic aspect of the Z-dependent differential conductance in SDM-based NS junctions can be ascribed to the novel pseudo-spin textures of SDMs as well as the unique band structures of SDMs intermediate between the linear and quadratic spectra.…”

Section: Effects Of the Interfacial Barriermentioning

confidence: 99%

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Orientation-dependent crossover from retro to specular Andreev reflections in semi-Dirac materials

Ouyang

2022

New J. Phys.

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In the framework of Bogoliubov-de Gennes equation, we theoretically study the Andreev reflection in normal-superconducting junctions based on semi-Dirac materials. Owing to the intrinsic anisotropy of semi-Dirac materials, the configuration of Andreev reflection and the differential conductance are strongly orientation-dependent. For the transport along the linear dispersion direction, the differential conductance exhibits a clear crossover from retro Andreev reflection to specular Andreev reflection with an increasing bias-voltage, and the differential conductance oscillates without a decaying profile when the interfacial barrier strength increases. However, for the transport along the quadratic dispersion direction, the boundary between the retro Andreev reflection and specular Andreev reflection is ambiguous, and the differential conductance decays with increasing the momentum mismatch or the interfacial barrier strength. We illustrate the pseudo-spin textures to reveal the underling physics behind the anisotropic coherent transport properties. These results enrich the understanding of the superconducting coherent transport in semi-Dirac materials.

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Section: Model and Methodsmentioning

confidence: 99%

Section: Effects Of the Interfacial Barriermentioning

confidence: 99%

Orientation-dependent crossover from retro to specular Andreev reflections in semi-Dirac materials

Ouyang

2022

New J. Phys.

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“…Violation of Lorentz symmetry in Weyl semimetals gives rise to distinguished transport features. Heterostructures of normal and superconducting Weyl II semimetals are shown to exhibit double Andreev reflections [6], double electron cotunnelling [7], signatures of non-local transport characterized by crossed Andreev reflections [8]. These properties are in contrast to the WSM type-I junctions [9], or junctions hosting Dirac fermions [10].…”

Section: Introductionmentioning

confidence: 97%

Theory of universal differential conductance of magnetic Weyl type -II junctions

Maiti,

Smotlacha

2020

Preprint

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We study the transport properties of junctions of normal and superconducting Weyl semi-metal with tilted dispersion, in the presence of magnetization induced by magnetic strips. The sub gap tunnelling conductance shows robust signatures in the presence of different orientation and strength of magnetization of the magnetic strips. We obtain the analytical results for the normal-magneticsuperconducting junction in the thin barrier limit and demonstrate that these results have no analogues to their conventional counterparts and junctions with Dirac electrons in two-dimensions. We discuss possible experimental setups to test our theoretical predictions.

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“…1. Separation of countermoving Fermi arcs to opposite surfaces explains their relevance at large systems sizes, most prominently in the intrinsic anomalous Hall effect [34,[37][38][39]. The relevance of finite-size effects for the valley degree of freedom, on the other hand, is much less obvious, since the valleys consist of extended bulk states, lacking…”

Section: Introductionmentioning

confidence: 99%

Chiral anomaly trapped in Weyl metals: Nonequilibrium valley polarization at zero magnetic field

Perez-Piskunow

Bovenzi²,

Akhmerov

et al. 2021

SciPost Phys.

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In Weyl semimetals, the application of parallel electric and magnetic fields leads to valley polarization---an occupation disbalance of valleys of opposite chirality---a direct consequence of the chiral anomaly. In this work, we present numerical tools to explore such nonequilibrium effects in spatially confined three-dimensional systems with a variable disorder potential, giving exact solutions to leading order in the disorder potential and the applied electric field. Application to a Weyl-metal slab shows that valley polarization also occurs without an external magnetic field as an effect of chiral anomaly ``trapping'': Spatial confinement produces chiral bulk states, which enable the valley polarization in a similar way as the chiral states induced by a magnetic field. Despite its finite-size origin, the valley polarization can persist up to macroscopic length scales if the disorder potential is sufficiently long ranged, so that direct inter-valley scattering is suppressed and the relaxation then goes via the Fermi-arc surface states.

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Nonlocal transport in superconducting heterostructures based on Weyl semimetals

Cited by 11 publications

References 45 publications

Orientation-dependent crossover from retro to specular Andreev reflections in semi-Dirac materials

Orientation-dependent crossover from retro to specular Andreev reflections in semi-Dirac materials

Theory of universal differential conductance of magnetic Weyl type -II junctions

Chiral anomaly trapped in Weyl metals: Nonequilibrium valley polarization at zero magnetic field

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