Multichannel superconductivity of monolayer FeSe on 
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: Interplay of spin fluctuations and electron-phonon interaction

Schrodi, Fabian; Aperis, Alex; Oppeneer, Peter M.

doi:10.1103/physrevb.102.180501

Cited by 20 publications

(17 citation statements)

References 48 publications

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“…These large repulsive peaks allow pairing with a sign-change across the BZ thus providing a mechanism for unconventional superconductivity in a manner similar to spin fluctuations. However, in contrast to the latter, where the small wavevector part of the repulsive interaction can interfere destructively to pairing [36][37][38], in our case the EPI remains attractive at smaller wavevectors and therefore can contribute to the unconventional pairing. We therefore conclude that the vertex-corrected EPI in all three prototypical examples is selfconsistently optimized so as to maximize the pairing.…”

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confidence: 56%

Unconventional superconductivity mediated solely by isotropic electron-phonon interaction

2021

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confidence: 56%

Unconventional superconductivity mediated solely by isotropic electron-phonon interaction

2021

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“…This aspect of our approach differs from the related work in Ref. [37], and we argue it is crucial for unifying the incipient 𝑠 ± and forward-scattering e-ph scenarios described above.…”

Section: Introductionmentioning

confidence: 84%

“…Based on this evidence, it is quite likely that both spin fluctuations and e-ph coupling are relevant to the FeSe monolayers. Until recently [37], however, no studies have been carried out for this system where these two contributions are treated on an equal footing. Here, we address this question directly and study the effects of combined spin fluctuations and small-q e-ph coupling using a fully self-consistent ME + Fluctuation-Exchange (FLEX) formalism.…”

Section: Introductionmentioning

confidence: 99%

Enhanced superconductivity in FeSe/SrTiO$_3$ from the combination of forward scattering phonons and spin fluctuations

Rademaker,

Alvarez-Suchini,

Nakatsukasa

et al. 2021

Preprint

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We study the effect of combining spin fluctuations and forward scattering electron-phonon (eph) coupling on the superconductivity in the FeSe/SrTiO3 system modeled by a phenomenological two-band Hubbard model with long-range e-ph interactions. We treat the electron and phonon degrees of freedom on an equal footing using a fully self-consistent FLEX plus Migdal-Eliashberg calculation, which includes a self-consistent determination of the spin fluctuation spectrum. Based on FeSe monolayers, we focus on the case where one of the bands lies below the Fermi level (i.e. incipient), and demonstrate that the combined interactions can enhance or suppress 𝑇𝑐, depending on their relative strength. For a suitable choice of parameters, the spin-fluctuation mechanism yields a 𝑇𝑐 ≈ 46.8 K incipient 𝑠± superconductor, consistent with surface-doped FeSe thin films. A forward-focused e-ph interaction further enhances the 𝑇𝑐, as observed in monolayer FeSe on SrTiO3.

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“…Here we discuss the EPI obtained by DFT calculations in Section III A and show how to calculate spinfluctuation kernels within the Random Phase Approximation (RPA) in Section III B. All calculations presented from here on, including Section IV, are carried out with the Uppsala Superconductivity (UppSC) code [41][42][43][44][45], partially with input from the Quantum Espresso package.…”

Section: Bosonic Interactionsmentioning

confidence: 99%

Exploring multichannel superconductivity in ThFeAsN

Schrodi,

Kabeer,

Aperis

et al. 2021

Preprint

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We investigate theoretically the superconducting state of the undoped Fe-based superconductor ThFeAsN. Using input from ab initio calculations, we solve the Fermi-surface based, multichannel Eliashberg equations for Cooper-pair formation mediated by spin and charge fluctuations, and by the electron-phonon interaction (EPI). Our results reveal that spin fluctuations alone, when coupling only hole-like with electron-like energy bands, can account for a critical temperature Tc up to ∼ 7.5 K with an s±-wave superconducting gap symmetry, which is a comparatively low Tc with respect to the experimental value T exp c = 30 K. Other combinations of interaction kernels (spin, charge, electronphonon) lead to a suppression of Tc due to phase frustration of the superconducting gap. We qualitatively argue that the missing ingredient to explain the gap magnitude and Tc in this material is the first-order correction to the EPI vertex. In the noninteracting state this correction adopts a form supporting the s± gap symmetry, in contrast to EPI within Migdal's approximation, i.e., EPI without vertex correction, and therefore it enhances tendencies arising from spin fluctuations.

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Multichannel superconductivity of monolayer FeSe on SrTiO3 : Interplay of spin fluctuations and electron-phonon interaction

Cited by 20 publications

References 48 publications

Unconventional superconductivity mediated solely by isotropic electron-phonon interaction

Unconventional superconductivity mediated solely by isotropic electron-phonon interaction

Enhanced superconductivity in FeSe/SrTiO$_3$ from the combination of forward scattering phonons and spin fluctuations

Exploring multichannel superconductivity in ThFeAsN

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