Zero-field superconducting diode effect in small-twist-angle trilayer graphene

Lin, Jiangxiazi; Siriviboon, Phum; Scammell, Harley D.; Liu, Song; Rhodes, Daniel; Watanabe, K.; Taniguchi, T.; Hone, James; Scheurer, Mathias S.; Li, J. I. A.

doi:10.48550/arxiv.2112.07841

Cited by 14 publications

(47 citation statements)

References 40 publications

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“…Note that, when finalizing this work, another zero-field superconducting diode effect has been experimentally observed in a twisted trilayer graphene and WSe 2 heterostructure [42].…”

Section: Sc Scmentioning

confidence: 69%

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General theory of Josephson Diodes

Zhang¹,

Gu²,

Hu³

et al. 2021

Preprint

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“…Note that, when finalizing this work, another zero-field superconducting diode effect has been experimentally observed in a twisted trilayer graphene and WSe 2 heterostructure [42].…”

Section: Sc Scmentioning

confidence: 69%

“…Although the setup is slightly different from that discussed in our work, the underlying physics is the same, where an internal time-reversal symmetry breaking and the interface proximity contribute the nonreciprocal transport [42]. And the flat band of the twisted trilayer graphene may enhance the nonreciprocal effect as in the NSB case.…”

Section: Sc Scmentioning

confidence: 73%

General theory of Josephson Diodes

Zhang¹,

Gu²,

Hu³

et al. 2021

Preprint

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“…The valence and conduction bands can be further aligned through spin splitting the bands via a TMDC layer [92,93], the effect of which can be tuned via twist angle [94]. Finally, valley polarisation is observed in twisted layered systems [95][96][97], which could also be exploited to align the valence and conduction bands, e.g. through methods discussed in [98,99].…”

Section: Discussionmentioning

confidence: 99%

Chiral excitonic order from twofold van Hove singularities in kagome metals

Scammell¹,

Ingham²,

Li³

et al. 2022

Preprint

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Recent experiments on kagome metals AV3Sb5 (A=K,Rb,Cs) [M. Kang et al., arXiv:2105.01689 (2021] identify twofold van Hove singularities (TvHS) with opposite concavity near the Fermi energy, generating two approximately hexagonal Fermi surfaces-one electron-like and the other hole-like.Here we propose that the TvHS are responsible for the novel charge and superconducting order observed in kagome metals. We introduce a model of a quasi-two dimensional system hosting a TvHS, and investigate the interaction induced many-body instabilities via the perturbative renormalisation group technique. The TvHS generates a topological d-wave excitonic condensate, arising due to bound pairs of electrons and holes located at opposite concavity vHS. Varying the chemical potential, detuning from the TvHS, and tuning the bare interaction strength, we construct a phase diagram which features the excitonic condensate alongside d-wave superconductivity and spin density wave order. The chiral excitonic state supports a Chern band giving rise to a quantum anomalous Hall conductance, providing an appealing interpretation of the observed anomalous Hall effect in kagome metals. Possible alternative realisations of the TvHS mechanism in bilayer materials are also discussed. We suggest that TvHS open up interesting possibilities for correlated phases, enriching the set of competing ground states to include excitonic order.

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“…Introduction.-A noncentrosymmetric material can support nonreciprocal charge transport, where the electrical resistance becomes different if the direction of the charge current is reversed. Recently, nonreciprocal phenomena in superconductors have become an active research topic [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. In bulk metals without the inversion symmetry, nonreciprocal charge transport occurs when the time-reversal symmetry is also broken.…”

mentioning

confidence: 99%

“…Moreover, in the superconducting state below T c , the critical current along opposite directions differs, i.e., j c (n) = j c (−n), where j c (n) represents the magnitude of critical current along direction n. This nonreciprocity results in the superconducting diode effect (SDE) [7], where the system is superconducting in one direction but resistive in the opposite direction if the applied current has a magnitude between j c (n) and j c (−n). The SDE has recently been observed experimentally in several systems [7][8][9][10][11][12], including an artifcial superlattice [Nb/V/Ta] n [7] and a heterostructure of twisted trilayer graphene and WSe 2 [12]. Theory on the SDE has been developed based on Ginzburg-Landau free energy as wel as microscopic calculation [13][14][15][16].…”

mentioning

confidence: 99%