Specular Andreev reflection in thin films of topological insulators

Majidi, Leyla; Asgari, Reza

doi:10.1103/physrevb.93.195404

Cited by 29 publications

(21 citation statements)

References 30 publications

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“…Our results are in agreement with those obtained for the case of singlelayer graphene [18], but do not coincide with the ones of Ref. [21] for a 3DTI. In the limit of Andreev retroreflection, the differential conductance at zero applied bias is equal to 4/3G 0 (eV ), than increases to a value of 2G 0 (eV ) at the gap eV = ∆, whereas in the limit of Andreev specular-reflection is equal to 2G 0 (eV ) at zero applied bias and it decreases to 4/3G 0 (eV ) for an applied voltage equal to the gap.…”

Section: Resultssupporting

confidence: 51%

“…This is realized on the surface of a 3DTI. We consider the insulator thick enough to neglect the tunneling coupling between the top and bottom surfaces of the system [21]. The effective Hamiltonian describing one of the surface edge states of a 3DTI reads:…”

Section: A the Normal Regionmentioning

confidence: 99%

“…(14), however here we consider different temperature for the normal and the superconducting regions. Equation (21) depends not only on the way electrons couples to the bath via the phonons but also on the number N of conducting channels in the normal regions.…”

Section: A Cooling Powermentioning

confidence: 99%

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Quasiparticle cooling using a topological insulator–superconductor hybrid junction

Bercioux

Lucignano

2018

Eur. Phys. J. Spec. Top.

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In this work, we investigate the thermoelectric properties of a hybrid junction realised coupling surface states of a three-dimensional topological insulator with a conventional s-wave superconductor. We focus on the ballistic devices and study the quasiparticle flow, carrying both electric and thermal currents, adopting a scattering matrix approach based on conventional Blonder-Tinkham-Klapwijk formalism. We calculate the cooling efficiency of the junction as a function of the microscopic parameters of the normal region (i.e. the chemical potential etc.). The cooling power increases when moving from a regime of Andreev specular-reflection to a regime where Andreev retro-reflection dominates. Differently from the case of a conventional N/S interface, we can achieve efficient cooling of the normal region, without including any explicit impurity scattering at the interface, to increase normal reflection.PACS numbers:

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Section: Resultssupporting

confidence: 51%

Section: A the Normal Regionmentioning

confidence: 99%

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Quasiparticle cooling using a topological insulator–superconductor hybrid junction

Bercioux

Lucignano

2018

Eur. Phys. J. Spec. Top.

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“…One typical result is the specular AR, which has been discovered with the hole reflected along a specular path of the incident electron in the NS junction based on the graphene-like materials [1,11]. And the perfect AR has been proposed and discovered in the NS junction of topological insulator [12,13]. Besides, in the SNS junction of topological SCs, the fractional Josephson effect is allowed to come into being [14,15].…”

Section: Introductionmentioning

confidence: 99%

Double Andreev reflections and double electron transmissions in a normal-superconductor-normal junction based on type-II Weyl semimetal

Zhang

Sun

et al. 2018

New J. Phys.

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We study the quantum transport behavior of a normal-superconductor-normal junction based on a type-II Weyl semimetal, which is arranged in the tilting direction of the Weyl semimetal. We find that both the crossed Andreev reflection and normal reflection are forbidden, while there will be double Andreev reflections and double electron transmissions for the incident electron from the semimetal side. Andreev reflections and transmissions occur both in the retro and specular directions simultaneously, symmetric about the normal of the interface but with different amplitudes, depending on the angle and energy of incident electrons. These transport processes make the junction here quite different from that based on the normal metal or graphene. In addition, the differential conductance is studied for experimental signatures. We find that the conductance is almost unaffected by the electrostatic potential in the normal region and it is enhanced with increasing junction length.

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“…SAR was not predicated until Beenakker [2,3] discovered that this rare phenomena is possible for relativistic electrons in graphene with a superconducting interface. Since then there have been many proposals about SAR in different systems like topological insulator-superconductor junction [4] and two-dimensional semiconductor with spin-orbit coupling and d-wave superconductor [5] etc. However, experimentally it remains challenging to observe this effect.…”

mentioning

confidence: 99%

Andreev reflection near the Dirac point at the graphene- NbSe2 junction

2016

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Despite extensive search for about a decade, specular Andreev reflection is only recently realized in bilayer graphene-superconductor interface. However, the evolution from the typical retro type Andreev reflection to the unique specular Andreev reflection in single layer graphene has not yet been observed. We investigate this transition by measuring the differential conductance at the van der Walls interface of single layer graphene and N bSe2 superconductor. We find that the normalized conductance (GT T c) becomes suppressed as we pass through the Dirac cone via tuning the Fermi level and bias energy, which manifests the transition from retro to non-retro type Andreev reflection. The suppression indicates the blockage of Andreev reflection beyond a critical angle (θc) of the incident electron with respect to the normal between the single layer graphene and the superconductor junction. The results are compared with a theoretical model of the corresponding setup.arXiv:1606.02559v1 [cond-mat.mes-hall]

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Specular Andreev reflection in thin films of topological insulators

Cited by 29 publications

References 30 publications

Quasiparticle cooling using a topological insulator–superconductor hybrid junction

Quasiparticle cooling using a topological insulator–superconductor hybrid junction

Double Andreev reflections and double electron transmissions in a normal-superconductor-normal junction based on type-II Weyl semimetal

Andreev reflection near the Dirac point at the graphene- NbSe2 junction

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