Odd-frequency superconductivity in a nanowire coupled to Majorana zero modes

Lee, Shu-Ping; Lutchyn, Roman M.; Maciejko, Joseph

doi:10.1103/physrevb.95.184506

Cited by 35 publications

(60 citation statements)

References 49 publications

(70 reference statements)

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“…First of all, we verify that keeping the disorder real (D φ = 0) reproduces the robustness of the induced SC correlations, as also found in Ref. 30, and that regardless of the value of s (the sign bias of the disorder), and also for relatively large magnitude disorder, up to D r = 1. Then, with the value of Γ 0 fixed, we generate 20 different random disorder configurations according to the distribution described in the introduction of Sec.…”

Section: Numerical Resultssupporting

confidence: 86%

“…This is in notable contrast to the findings of Ref. 30, where the pair amplitude was assumed to always be proportional to real couplings. If Γ is real, it does not present any issues for the pair amplitudes, however, it does when Γ is complex.…”

Section: A Spw Coupled To a Single Mzmcontrasting

confidence: 96%

“…We stress that this behavior is thus very different for the effect of real disorder, where the pair amplitudes are robust. 30 The data in Fig. 4(a) are the odd-ω component directly under one of the MZMs.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Most importantly, based on both analytical and numerical approaches, we demonstrate that even moderate phase disorder in the couplings drastically suppresses the induced SC in the SPW, in stark contrast to the effect of real disorder where even large variations of the couplings has been shown to only produce very small changes. 30 Furthermore, we show that the suppression of the induced pair correlations is accompanied by the filling of the energy gap in the density of states (DOS) due to formation of bound states in the SPW. As a consequence, our work shows that experimental realizations of a 1D odd-ω superconductor from an array of MZMs must have full control of the phases of the couplings.…”

Section: Introductionmentioning

confidence: 88%

“…This directly results in the A 2 -term being the dominant term in the square brackets expression in Eq. (30). However, this term also contains a factor of g eh 1 that, according to Eqs.…”

Section: Spw Coupled To a Mzm Arraymentioning

confidence: 99%

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Suppression of odd-frequency pairing by phase disorder in a nanowire coupled to Majorana zero modes

2020

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Odd-frequency superconductivity is an exotic phase of matter in which Cooper pairing between electrons is entirely dynamical in nature. Majorana zero modes exhibit pure odd-frequency superconducting correlations due to their specific properties. Thus, by tunnel-coupling an array of Majorana zero modes to a spin-polarized wire, it is in principle possible to engineer a bulk onedimensional odd-frequency spinless s-wave superconductor. We here point out that each tunnel coupling element, being dependent on a large number of material-specific parameters, is generically complex with sample variability in both its magnitude and phase. Using this, we demonstrate that, upon averaging over phase-disorder, the induced superconducting, including odd-frequency, correlations in the spin-polarized wire are significantly suppressed. We perform both a rigorous analytical evaluation of the disorder-averaged T -matrix in the wire, as well as numerical calculations based on a tight-binding model, and find that the anomalous, i.e. superconducting, part of the T -matrix is highly suppressed with phase disorder. We also demonstrate that this suppression is concurrent with the filling of the single-particle excitation gap by smearing the near-zero frequency peaks, due to formation of bound states that satisfy phase-matching conditions between spatially separated Majorana zero modes. Our results convey important constraints on the parameter control needed in practical realizations of Majorana zero mode structures and suggest that the achievement of a bulk 1D odd-ω superconductivity from MZMs demand full control of the system parameters.

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Section: Numerical Resultssupporting

confidence: 86%

Section: A Spw Coupled To a Single Mzmcontrasting

confidence: 96%

Section: Numerical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

“…This directly results in the A 2 -term being the dominant term in the square brackets expression in Eq. (30). However, this term also contains a factor of g eh 1 that, according to Eqs.…”

Section: Spw Coupled To a Mzm Arraymentioning

confidence: 99%

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Suppression of odd-frequency pairing by phase disorder in a nanowire coupled to Majorana zero modes

2020

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The Role of Odd‐Frequency Pairing in Multiband Superconductors

2020

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Recent progress in the understanding of multiband superconductivity and its relationship to odd‐frequency pairing are reviewed herein. The discussion begins by reviewing the emergence of odd‐frequency pairing in a simple two‐band model, providing a brief pedagogical overview of the formalism. Several examples of multiband superconducting systems are examined, in each case describing both the origin of the band degree of freedom and the nature of the odd‐frequency pairing. Throughout, it is attempted to convey a unified picture of how odd‐frequency pairing emerges in these materials and propose that similar mechanisms are responsible for odd‐frequency pairing in several analogous systems: layered 2D heterostructures, double quantum dots, double nanowires, Josephson junctions, and systems described by isolated valleys in momentum space. In addition, experimental probes of odd‐frequency pairing in multiband systems are reviewed, focusing on hybridization gaps in the electronic density of states, paramagnetic Meissner effect, and Kerr effect.

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Proximity-induced supercurrent through topological insulator based nanowires for quantum computation studies

Bhattacharyya

Awana

Senguttuvan

et al. 2018

Sci Rep

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Proximity-induced superconducting energy gap in the surface states of topological insulators has been predicted to host the much wanted Majorana fermions for fault-tolerant quantum computation. Recent theoretically proposed architectures for topological quantum computation via Majoranas are based on large networks of Kitaev’s one-dimensional quantum wires, which pose a huge experimental challenge in terms of scalability of the current single nanowire based devices. Here, we address this problem by realizing robust superconductivity in junctions of fabricated topological insulator (Bi2Se3) nanowires proximity-coupled to conventional s-wave superconducting (W) electrodes. Milling technique possesses great potential in fabrication of any desired shapes and structures at nanoscale level, and therefore can be effectively utilized to scale-up the existing single nanowire based design into nanowire based network architectures. We demonstrate the dominant role of ballistic topological surface states in propagating the long-range proximity induced superconducting order with high IcRN product in long Bi2Se3 junctions. Large upper critical magnetic fields exceeding the Chandrasekhar-Clogston limit suggests the existence of robust superconducting order with spin-triplet cooper pairing. An unconventional inverse dependence of IcRN product on the width of the nanowire junction was also observed.

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Odd-frequency superconductivity in a nanowire coupled to Majorana zero modes

Cited by 35 publications

References 49 publications

Suppression of odd-frequency pairing by phase disorder in a nanowire coupled to Majorana zero modes

Suppression of odd-frequency pairing by phase disorder in a nanowire coupled to Majorana zero modes

The Role of Odd‐Frequency Pairing in Multiband Superconductors

Proximity-induced supercurrent through topological insulator based nanowires for quantum computation studies

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