Nonlocal Thermoelectricity in a Superconductor–Topological-Insulator–Superconductor Junction in Contact with a Normal-Metal Probe: Evidence for Helical Edge States

Blasi, Gianmichele; Taddei, F.; Arrachea, Liliana; Carrega, Matteo; Braggio, Alessandro

doi:10.1103/physrevlett.124.227701

Cited by 52 publications

(40 citation statements)

References 64 publications

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“…Moreover, we found that the zero bias conductance quantization remains unchanged as we moved the probe along the edge, remarkably, even for distances much larger than the localization length of the Majorana states. This result can not be simply explained by the local density of states in the tunneling model [52][53][54]. Our analytical results suggested that the spatial independence of the zero-bias tip conductance results from a coherent coupling to the zero-energy Majorana bound states.…”

mentioning

confidence: 75%

“…We only consider one edge, assuming negligible overlap between different edge states due to a large width of the QSHI. A similar three-terminal setup with a metallic tip has been proposed to detect the helical nature of the edge states or to design novel applications [49][50][51][52][53][54][55]. Here, we focus on the detection of MBSs and consider both superconducting and magnetic regions, which open gaps on the helical edge channel forming the FS and SFS junctions featured in, respectively, Fig.…”

mentioning

confidence: 99%

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Identifying Majorana bound states at quantum spin Hall edges using a metallic probe

Lu¹,

Cheng²,

Burset³

et al. 2021

Preprint

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We study the conductance afforded by a normal-metal probe which is directly contacting the helical edge modes of a quantum spin Hall insulator (QSHI). We show a 2e 2 /h conductance peak in QSHI-based superconductor-ferromagnet hybrids due to the formation of a single Majorana bound state (MBS). In a corresponding Josephson junction hosting a pair of MBSs, a 4e 2 /h conductance peak is found. The conductance quantization is robust to changes of the relevant system parameters and, remarkably, remains unaltered with increasing the distance between probe and MBSs. Our findings can therefore provide an effective way to detect the existence of MBSs in QSHI systems.

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confidence: 75%

mentioning

confidence: 99%

Identifying Majorana bound states at quantum spin Hall edges using a metallic probe

Lu¹,

Cheng²,

Burset³

et al. 2021

Preprint

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“…Thermal response of quantum hall edge has already being studies in experiment [44] and hence an similar experimental set-up involving the spin Hall edge may not be far in the future. Recent theoretical studies have explored the possibility of inducing thermoelectric effect in helical edge state-based Josephson junction involving either an anisotropic ferromagnetic barrier [45,46] or a threeterminal geometry [47][48][49]. In this work we show that thermoelectric effect can exist in the HES of QSH even in a simplest case of two terminal ballistic JJ owing to breaking of the ω → −ω symmetry of the quasi-particle transmission probabilities across the junction at finite length.…”

Section: Introductionmentioning

confidence: 82%

Thermoelectric response of Josephson junction: from ballistic to disordered

Mukhopadhyay¹,

Das²

2021

Preprint

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It is known that Josephson junction (JJ) hosting scattering centers with energy dependent scattering amplitudes which breaks the ω → −ω symmetry (where ω is the excitation energy of electron about the Fermi level) exhibits finite thermoelectric response. In contrast, here we show that even in a ballistic JJ this symmetry is broken and it leads to a non-zero thermoelectric response when the junction length is of the order of coherence length of the superconductor and the corresponding thermoelectric coefficient confirms to the universal sinusoidal dependence on φ12, where φ12 is the superconducting phase bias. In presence of multiple scatterers in the junction region, we have numerically shown that the sign of the even-in-φ12 part of the thermoelectric coefficient fluctuates violently from one disorder configuration to another hence averaging to vanishingly small values while the odd part tends towards the universal sinusoidal dependence on φ12 as we approach the large disorder limit under disorder averaging.

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“…M esoscopic thermoelectric effects have been investigated in a variety of condensed matter systems that, besides fundamental normal metal-superconductor-normal metal (NSN) systems [1][2][3][4][5] , also include quantum dots [6][7][8][9][10] , atomic point contacts [11][12][13] , Andreev interferometers 14,15 , superconducting rings 16 and nanowire heat engines 17 . Thermoelectric effects in the superconducting systems [18][19][20][21][22] , in particular those dealing with non-local thermoelectric currents in superconductor-ferromagnet devices [23][24][25] and in bulk nonmagnetic hybrid NSN structures [26][27][28] have attracted special attention. The connection between thermoelectric effects and the Cooper pair splitting (CPS) 1,2 , proposed in ref.…”

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confidence: 99%

Thermoelectric current in a graphene Cooper pair splitter

et al. 2021

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Generation of electric voltage in a conductor by applying a temperature gradient is a fundamental phenomenon called the Seebeck effect. This effect and its inverse is widely exploited in diverse applications ranging from thermoelectric power generators to temperature sensing. Recently, a possibility of thermoelectricity arising from the interplay of the non-local Cooper pair splitting and the elastic co-tunneling in the hybrid normal metal-superconductor-normal metal structures was predicted. Here, we report the observation of the non-local Seebeck effect in a graphene-based Cooper pair splitting device comprising two quantum dots connected to an aluminum superconductor and present a theoretical description of this phenomenon. The observed non-local Seebeck effect offers an efficient tool for producing entangled electrons.

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Nonlocal Thermoelectricity in a Superconductor–Topological-Insulator–Superconductor Junction in Contact with a Normal-Metal Probe: Evidence for Helical Edge States

Cited by 52 publications

References 64 publications

Identifying Majorana bound states at quantum spin Hall edges using a metallic probe

Identifying Majorana bound states at quantum spin Hall edges using a metallic probe

Thermoelectric response of Josephson junction: from ballistic to disordered

Thermoelectric current in a graphene Cooper pair splitter

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