Catalog of Andreev spectra and Josephson effects in structures with time-reversal-invariant topological superconductor wires

Arrachea, Liliana; Camjayi, Alberto; Aligia, A. A.; Gruñeiro, Leonel José

doi:10.1103/physrevb.99.085431

Cited by 17 publications

(9 citation statements)

References 69 publications

(92 reference statements)

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“…On one hand, in a TRITOPS Josephson junction that preserves T at phase differences 0 and π, each subgap level is certainly 4π periodic (Fig. 1), suggesting that a fractional Josephson effect appears as predicted in numerous works [26,29,30,43,[49][50][51][52][53][54][55][56][57]. But on the other, the braiding and fractional Josephson connection noted earlier naively implies that nonuniversality of the former spells doom for the latter.…”

mentioning

confidence: 66%

Fragility of the Fractional Josephson Effect in Time-Reversal-Invariant Topological Superconductors

2020

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Time-reversal-invariant topological superconductor (TRITOPS) wires host Majorana Kramers pairs that have been predicted to mediate a fractional Josephson effect with 4π periodicity in the superconducting phase difference. We explore the TRITOPS fractional Josephson effect in the presence of time-dependent "local mixing" perturbations that instantaneously preserve time-reversal symmetry. Specifically, we show that just as such couplings render braiding of Majorana Kramers pairs nonuniversal, the Josephson current becomes either aperiodic or 2π periodic (depending on conditions that we quantify) unless the phase difference is swept sufficiently quickly. We further analyze topological superconductors with T 2 ¼ þ1 time-reversal symmetry and reveal a rich interplay between interactions and local mixing that can be experimentally probed in nanowire arrays.

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confidence: 66%

Fragility of the Fractional Josephson Effect in Time-Reversal-Invariant Topological Superconductors

2020

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“…[11][12][13][14] The QDs' highly tunable electronic spectra [15][16][17][18] makes them in particular interesting for low-dissipation superconducting spintronics 19,20 and quantum computation. 21,22 Ground-state (GS) transitions in such systems have been observed [23][24][25][26] and discussed in terms of the spin-orbit interaction 27,28 , topological protection, [29][30][31][32][33] and nonequilibrium transport. [34][35][36][37] Remarkably, it was recently demonstrated in carbon nanotube (CNT) quantum dot setups that the electron-phonon interaction can be tailored electrostatically, to even attain attractive electron interaction.…”

Section: Introductionmentioning

confidence: 99%

Resonator induced quantum phase transitions in a hybrid Josephson junction

Hussein,

Belzig

2021

Preprint

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We investigate the Josephson current through a suspended carbon nanotube double quantum dot which, at sufficiently low temperatures, is characterized by the ground state of the electronic subsystem. Depending on parameters like a magnetic field or the inter-dot coupling, the ground state can either be a current-carrying singlet or doublet, or a blockaded triplet state. Since the electron-vibration interaction has been demonstrated to be electrostatically tuneable, we study in particular its effect on the current-phase relation. We show that the coupling to the vibration mode can lift the current-suppressing triplet blockade by inducing a quantum phase transition to a ground state of a different total spin. Our key finding is the development of a triple point in the Josephson current parameterized by the resonator coupling and the Josephson phase. The quantum phase transitions around the triple point are directly accessible through the critical current and resilient to moderately finite temperatures. The proposed setup makes the mechanical degree of freedom part of a superconducting hybrid device which is interesting for ultra-sensitive displacement detectors.

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“…More recently, there has been experimental research as well as theoretical studies in similar models, including those for time-reversal invariant topological superconductors, 12,13 of the effects of MZMs in Josephson junctions, in particular because the dependence on the applied magnetic flux introduces an additional control knob. [13][14][15][16][17][18][19][20] In particular, it has been recently proposed that the current-phase relation measured in Josephson junctions may be used to find the parameters that define the MZMs. 20 A possible difficulty in these experiments is the slow thermalization to the ground state in the presence of a gap.…”

Section: Introductionmentioning

confidence: 99%

Phase diagram of a model for topological superconducting wires

Daroca

Aligia

2021

Phys. Rev. B

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We calculate the phase diagram of a model for topological superconducting wires with local swave pairing, spin-orbit coupling λ and magnetic field B with arbitrary orientations. This model is a generalized lattice version of the one proposed by Lutchyn et al. [Phys. Rev. Lett. 105 077001 (2010)] and Oreg et al. [Phys. Rev. Lett. 105 177002 (2010)], who considered λ perpendicular to B. The model has a topological gapped phase with Majorana zero modes localized at the ends of the wires. We determine analytically the boundary of this phase. When the directions of the spin-orbit coupling and magnetic field are not perpendicular, in addition to the topological phase and the gapped non-topological phase, a gapless superconducting phase appear.

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Catalog of Andreev spectra and Josephson effects in structures with time-reversal-invariant topological superconductor wires

Cited by 17 publications

References 69 publications

Fragility of the Fractional Josephson Effect in Time-Reversal-Invariant Topological Superconductors

Fragility of the Fractional Josephson Effect in Time-Reversal-Invariant Topological Superconductors

Resonator induced quantum phase transitions in a hybrid Josephson junction

Phase diagram of a model for topological superconducting wires

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