Quantum geometric effect on Fulde-Ferrell-Larkin-Ovchinnikov superconductivity

Kitamura, Taisei; Daido, Akito; Yanase, Youichi

doi:10.1103/physrevb.106.184507

Cited by 11 publications

(2 citation statements)

References 95 publications

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“…For example, it remains to be answered whether a quantum geometry can stabilize quantum order like anti-ferromagnetic and charge density wave. It also is appealing to realize a novel quantum phases by designing a multi-orbital system with nontrivial quantum geometry [71][72][73] such as pair density wave order. Since the develop GL theory is flexible in the isolated band system, it inspires us to consider the role of quantum geometry of a broaden fields, such as electron-phonon interaction, magnetism and etc.…”

Section: πmentioning

confidence: 99%

Towards a Ginzburg-Landau theory of the quantum geometric effect in superconductors

Chen¹,

Law²

2023

Preprint

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Superconductivity in flat-band systems, such as twisted bilayer graphene, exhibits unconventional behaviours which cannot be described by the BCS theory. In this work, we derive an effective Lagrangian from a microscopic flat-band Hamiltonian which allows us to establish a Ginzburg-Landau (GL) theory includes the quantum geometric effects in flat-band superconductors. First of all, we deduce the the critical temperature of a flat-band superconductor within the mean field description which is determined by the quantum metric. Secondly, going beyond the mean-field approximation by taking into account the fluctuations of the order parameter, we determine the superfluid weight, superconducting coherent length and the upper critical field and their dependence on the quantum metric of the flat bands. Thirdly, we apply the GL to twisted bilayer graphene (TBG). By calculating the quantum metric of flat bands of TBG, the GL theory allows the estimation of the superconducting coherence length and the upper critical field. The results of the superconducting coherence length and upper critical field match the experimental results incredibly well without the fine tuning of parameters. The GL theory with quantum metric provides a new and general theoretical understanding of unconventional behaviors of flat-band superconductors.

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Section: πmentioning

confidence: 99%

Towards a Ginzburg-Landau theory of the quantum geometric effect in superconductors

Chen¹,

Law²

2023

Preprint

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“…In the flatband systems [36,37,[47][48][49][50][51] the superfluid weight from Fermi-liquid theory vanishes, and the quantum geometric contribution determines the superfluid weight. The quantum geometry also plays essential roles in the monolayer FeSe [52] and some finite-momentum Cooper pairing states [53][54][55][56][57]. However, how quantum geometry affects the pairing mechanism of superconductivity has not been revealed.…”

mentioning

confidence: 99%

Spin-Triplet Superconductivity from Quantum-Geometry-Induced Ferromagnetic Fluctuation

Kitamura,

Daido,

Yanase

2024

Phys. Rev. Lett.

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We show that quantum geometry induces ferromagnetic fluctuation resulting in spin-triplet superconductivity. The criterion for ferromagnetic fluctuation is clarified by analyzing contributions from the effective mass and quantum geometry. When the non-Kramers band degeneracy is present near the Fermi surface, the Fubini-Study quantum metric strongly favors ferromagnetic fluctuation. Solving the linearized gap equation with the effective interaction obtained by the random phase approximation, we show that the spin-triplet superconductivity is mediated by quantum-geometry-induced ferromagnetic fluctuation.

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Pair density wave facilitated by Bloch quantum geometry in nearly flat band multiorbital superconductors

Chen

Wen

2023

Sci. China Phys. Mech. Astron.

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Quantum geometric effect on Fulde-Ferrell-Larkin-Ovchinnikov superconductivity

Cited by 11 publications

References 95 publications

Towards a Ginzburg-Landau theory of the quantum geometric effect in superconductors

Towards a Ginzburg-Landau theory of the quantum geometric effect in superconductors

Spin-Triplet Superconductivity from Quantum-Geometry-Induced Ferromagnetic Fluctuation

Pair density wave facilitated by Bloch quantum geometry in nearly flat band multiorbital superconductors

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