High-temperature topological superconductivity in twisted double-layer copper oxides

Can, Oguzhan; Tummuru, Tarun; Day, Robert W.; Elfimov, Ilya; Damascelli, A.; Franz, Marcel

doi:10.1038/s41567-020-01142-7

Cited by 142 publications

(155 citation statements)

References 42 publications

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“…V, we have considered a perturbation (16), which breaks the mirror symmetry in the x-direction. One possible way to break the mirror symmetry is to use twisted double-layered cuprate thin films [40,76]. Also, using a substrate lacking mirror symmetry might be another way.…”

Section: A Experimental Setupmentioning

confidence: 99%

Supercurrent-induced topological phase transitions

Takasan,

Sumita,

Yanase

2021

Preprint

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We show that finite current in superconductors can induce topological phase transitions, as a result of the deformation of the quasiparticle spectrum by a finite center-of-mass (COM) momentum of the Cooper pairs. To show the wide applicability of this mechanism, we examine the topological properties of three prototypical systems, the Kitaev chain, s-wave superconductors, and d-wave superconductors. We introduce a finite COM momentum as an external field corresponding to supercurrent and show that all the models exhibit current-induced topological phase transitions. We also discuss the possibility of observing the phase transitions in experiments and the relation to the other finite COM momentum pairing states.

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Section: A Experimental Setupmentioning

confidence: 99%

Supercurrent-induced topological phase transitions

Takasan,

Sumita,

Yanase

2021

Preprint

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“…The DFT calculations predicted the stability of this structure [93], which was recently experimentally fabricated, and definite evidences for coherent interlayer Josephson tunneling were detected [50,51]. In the theoretical aspect, although the G-L theory has predicted d + id TSC in this system [93], more information on the pairing state should be determined by microscopic calculations, which presently are limited to commensurate twisted angles. For general twisted angles, particularly the exact 45 • , our perturbational-band theory applies.…”

Section: + I P F + I F H + I H V H S ( B )mentioning

confidence: 97%

High-Angular-Momentum Topological Superconductivity in the Largest-Angle Twisted Homo-bilayer Systems

Liu¹,

Zhang²,

Chen³

et al. 2022

Preprint

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We study the largest-angle twisted homo-bilayer (LA-THB) systems, hosting Moiréless quasicrystal (QC) structure. We propose to use these materials to generate high-angular-momentum (HAM) topological superconductivities (TSCs) protected by their QC symmetries absent on conventional crystalline materials. This proposal is based on our universal Ginzburg-Landau theory based analysis which yields the general conclusion that, when each Dn-symmetric (n is even) monolayer hosts SC with pairing angular momentum l ≤ n 2 , the interlayer Josephson coupling will induce SC with pairing angular momentum L = l or L = n − l in the LA-THB, determined by microscopic details. The latter one is just the HAM TSC if l > 0. Based on our revised perturbational-band theory, we develop general microscopic framework to study the QC LA-THBs involving electronelectron interactions, adopting which we study three examples, i.e. the 30 • -twisted bilayer graphene, the 30 • -twisted bilayer BC3, and the 45 • -twisted bilayer cuprates. The g + ig-h + ih-and d + id-TSCs with HAM L = 4, 5 and 2 can emerge in certain doping regimes in these systems, respectively.

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“…The recent fabrication of high quality monolayer of Bi 2 Sr 2 CaCu 2 O 8 (Bi2212) [12] finds similar critical temperature in single-layer and bulk cuprates, opening up the experimental study of cuprates as essentially 2D system. This also enables the experimental study of twisted cuprate bilayer, which in turn has spurred pioneering theoretical proposals for two different realizations of topological superconductor in twisted cuprate bilayer [13,14]. Especially, Ref.…”

mentioning

confidence: 99%

“…Especially, Ref. 13 proposes a topological superconductor with time reversal symmetry spontaneously broken when the twist angle θ is around 45 • degree while Ref. 14 seeks to stabilize a similar state by tuning near a magic angle with weak quasiparticle dispersion and establishing a superflow along the 'c-axis'.…”

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confidence: 99%

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Doping a moiré Mott Insulator: A t-J model study of twisted cuprates

Song,

Zhang,

Vishwanath

2021

Preprint

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We theoretically investigate twisted structures where each layer is composed of a strongly correlated material. In particular, we study a twisted t-J model of cuprate multilayers within the slave-boson mean field theory. This treatment encompasses the Mott physics at small doping and self consistently generates d-wave pairing. Furthermore, including the correct inter-layer tunneling form factor consistent with the symmetry of the Cu d x 2 −y 2 orbital proves to be crucial for the phase diagram. We find spontaneous time reversal (T) breaking around twist angle of 45 • , although only in a narrow window of twist angles. Moreover, the gap obtained is small and the Chern number vanishes, implying a non-topological superconductor. At smaller twist angles, driving an interlayer current however can lead to a gapped topological phase. The energy-phase relation of the interlayer Josephson junction displays notable double-Cooper-pair tunneling which dominates around 45 o . The twist angle dependence of the Josephson critical current and the Shapiro steps are consistent with recent experiments. Utilizing the moiré structure as a probe of correlation physics, in particular of the pair density wave state, is discussed.1 Strictly speaking, the oxygen p orbital is also involved in hole doped cuprate, forming the Zhang-Rice singlet. However, the active Zhang-Rice singlet has the same symmetry as the Cu d x 2 −y 2 orbital and does not change our analysis.

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High-temperature topological superconductivity in twisted double-layer copper oxides

Cited by 142 publications

References 42 publications

Supercurrent-induced topological phase transitions

Supercurrent-induced topological phase transitions

High-Angular-Momentum Topological Superconductivity in the Largest-Angle Twisted Homo-bilayer Systems

Doping a moiré Mott Insulator: A t-J model study of twisted cuprates

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