Zero-bias conductance peak in Dirac semimetal-superconductor devices

Yu, Wenlong; Haenel, Rafael; Rodriguez, Mark A.; Lee, S. R.; Zhang, Fan; Franz, Marcel; Pikulin, Dmitry I.; Pan, W.

doi:10.1103/physrevresearch.2.032002

Cited by 16 publications

(11 citation statements)

References 41 publications

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“…Since in this case the low-bias conductance enhancement is not due to Andreev reflection, there is no upper limit of the ratio between the zero-bias conductance and the high-bias conductance. Under certain circumstances, as shown in Figure 1(f), the zero-bias conductance can even get exactly doubled thereby mimicking "perfect" Andreev reflection as is expected due to Klein tunneling in topological superconductors [19,21,31]. As shown in Figure 1(g), the zero-bias conductance can even become far greater than 2 and may look like a signature of robust zero-energy bound states [31].…”

mentioning

confidence: 81%

“…Under certain circumstances, as shown in Figure 1(f), the zero-bias conductance can even get exactly doubled thereby mimicking "perfect" Andreev reflection as is expected due to Klein tunneling in topological superconductors [19,21,31]. As shown in Figure 1(g), the zero-bias conductance can even become far greater than 2 and may look like a signature of robust zero-energy bound states [31].…”

mentioning

confidence: 81%

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Non-ballistic transport characteristics of superconducting point-contacts

Kumar,

Sheet

2020

Preprint

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In the "ballistic" regime, the transport across a normal metal (N)/superconductor (S) pointcontact is dominated by a quantum process called Andreev reflection. Andreev reflection causes an enhancement of the conductance below the superconducting energy gap, and the ratio of the low-bias and the high-bias conductance cannot be greater than 2 when the superconductor is conventional in nature. In this regime, the features associated with Andreev reflection also provide energy and momentum-resolved spectroscopic information about the superconducting phase. Here we theoretically consider various types of N/S point contacts, away from the ballistic regime, and show that even when the superconductor under investigation is simple conventional in nature, depending on the shape, size and anatomy of the point contacts, a wide variety of spectral features may appear in the conductance spectra. Such features may misleadingly mimic theoretically expected signatures of exotic physical phenomena like Klein tunneling in topological superconductors, Andreev bound states in unconventional superconductors, multiband superconductivity and Majorana zero modes.

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confidence: 81%

mentioning

confidence: 81%

Non-ballistic transport characteristics of superconducting point-contacts

Kumar,

Sheet

2020

Preprint

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“…Moreover, the transport data under magnetic fields reported anomalous behaviors that the conventional BCS theory cannot explain 27 , 29 , 32 . At ambient pressure, the proximity-induced superconductivity in is also reported 35 .…”

Section: Introductionmentioning

confidence: 88%

Emergence of topological superconductivity in doped topological Dirac semimetals under symmetry-lowering lattice distortions

Cheon

Lee

Chung

et al. 2021

Sci Rep

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Recently, unconventional superconductivity having a zero-bias conductance peak is reported in doped topological Dirac semimetal (DSM) with lattice distortion. Motivated by the experiments, we theoretically study the possible symmetry-lowering lattice distortions and their effects on the emergence of unconventional superconductivity in doped topological DSM. We find four types of symmetry-lowering lattice distortions that reproduce the crystal symmetries relevant to experiments from the group-theoretical analysis. Considering inter-orbital and intra-orbital electron density-density interactions, we calculate superconducting phase diagrams. We find that the lattice distortions can induce unconventional superconductivity hosting gapless surface Andreev bound states (SABS). Depending on the lattice distortions and superconducting pairing interactions, the unconventional inversion-odd-parity superconductivity can be either topological nodal superconductivity hosting a flat SABS or topological crystalline superconductivity hosting a gapless SABS. Remarkably, the lattice distortions increase the superconducting critical temperature, which is consistent with the experiments. Our work opens a pathway to explore and control pressure-induced topological superconductivity in doped topological semimetals.

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“…Indeed, for a NSN device at zero-temperature, the zero-bias SC conductance approaches G 0 (i.e. , the conductance of each NS interface approaches 2 × G 0 ) only if the electron transmission probability between the contacts and the normal-phase channel approaches unity in a finite window around the Fermi level [38][39][40][41] . Within the wide-band limit (WBL) approximation for the leads this happens when Γ = β.…”

Section: A Good Metal Contacts/strong Channel-electrodes Couplingmentioning

confidence: 99%

Nanoscale functionalized superconducting transport channels as photon detectors

Spataru,

Léonard

2021

Preprint

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Single-photon detectors have typically consisted of macroscopic materials where both the photon absorption and transduction to an electrical signal happen. Newly proposed designs suggest that large arrays of nanoscale detectors could provide improved performance in addition to decoupling the absorption and transduction processes. Here we study the properties of such a detector consisting of a nanoscale superconducting (SC) transport channel functionalized by a photon absorber. We explore two detection mechanisms based on photo-induced electrostatic gating and magnetic effects.To this end we model the narrow channel as a one-dimensional atomic chain and use a self-consistent Keldysh-Nambu Green's function formalism to describe non-equilibrium effects and SC phenomena. We consider cases where the photon creates electrostatic and magnetic changes in the absorber, as well as devices with strong and weak coupling to the metal leads. Our results indicate that the most promising case is when the SC channel is weakly coupled to the leads and in the presence of a background magnetic field, where photo-excitation of a magnetic molecule can trigger a SC-tonormal transition in the channel that leads to a change in the device current several times larger than in the case of a normal-phase channel device.

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Zero-bias conductance peak in Dirac semimetal-superconductor devices

Cited by 16 publications

References 41 publications

Non-ballistic transport characteristics of superconducting point-contacts

Non-ballistic transport characteristics of superconducting point-contacts

Emergence of topological superconductivity in doped topological Dirac semimetals under symmetry-lowering lattice distortions

Nanoscale functionalized superconducting transport channels as photon detectors

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