Two-gap superconductivity in heavily<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>n</mml:mi></mml:math>-doped graphene:<i>Ab initio</i>Migdal-Eliashberg theory

Margine, E. R.; Giustino, Feliciano

doi:10.1103/physrevb.90.014518

Cited by 81 publications

(67 citation statements)

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“…(For example, we examined the influence of * m and found that T c is lowered by~20% for * m~0.2 (see supplementary material 6 ). This is much smaller than the factor of 2-5 commonly obtained for conventional phonon-mediated pairing [42,43]. This robustness is linked to the same momentum decoupling responsible for the linear dependence of T c on l m .)…”

Section: Discussionmentioning

confidence: 73%

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO₃substrates

et al. 2016

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We study the consequences of an electron-phonon (e-ph) interaction that is strongly peaked in the forward scattering ( = q 0) direction in a two-dimensional superconductor using Migdal-Eliashberg theory. We find that strong forward scattering results in an enhanced T c that is linearly proportional to the strength of the dimensionless e-phcoupling constant l m in the weak coupling limit. This interaction also produces distinct replica bands in the single-particle spectral function, similar to those observed in recent angle-resolved photoemission experiments on FeSe monolayers on SrTiO 3 and BaTiO 3 substrates. By comparing our model to photoemission experiments, we infer an e-phcoupling strength that can provide a significant portion of the observed high T c in these systems.A flurry of scientific activities has been generated by the discovery of an enhanced superconductivity in FeSe monolayers grown on SrTiO 3 (STO) substrates [1-20]. On its own, bulk FeSe has a modest superconducting transition temperatureT 9 c K [21]; however, when a monolayer is grown on an STO substrate, T c is increased dramatically [1]. Most reported T c values cluster within 55-75 K, close to the boiling point of liquid nitrogen (77 K). (A surprisingly highT 107 c K has also been reported in in situ transport measurements [9].) This discovery has opened a pathway to high-T c superconductivity through interface engineering, which has already produced high-T c ʼs in systems such as FeSe on BaTiO 3 (BTO) [8] and FeTe -x 1 Se x on STO [22]. Determining the origin of the T c enhancement in these interface systems is critical. At the moment, proposals include charge transfer between the substrate and FeSe [2-4, 20], electric field [6] and strain effects due to the substrate [5, 8], and lattice related effects such as enhanced electron-phonon (e-ph) coupling in the FeSe layer [1,13,16] or across the interface [7,19]. Strong evidence for the latter has been provided by a recent angleresolved photoemission spectroscopy (ARPES) study [7], which observed replica bands in the single-particle spectral function of the FeSe monolayer. These replicas are interpreted as being produced by coupling between the FeSe d 3 electrons and an optical oxygen phonon branch in the STO substrate. Moreover, the replica bands are complete copies of the corresponding main bands, which implies that the responsible e-phinteraction is strongly peaked in the forward scattering direction (small momentum transfers). Such momentum dependence is notable because it can enhance superconductivity in most pairing channels [23][24][25][26][27][28][29][30][31]. As such, this crossinterface coupling provides at the same time a suitable mechanism for the T c enhancement in the FeSe/STO and FeSe/BTO systems [7,8].We explore this possibility here by examining the consequences of strong forward scattering in the e-phinteraction for superconductivity and the spectral properties of a two-dimensional system. By solving the momentum dependent Eliashberg equations, we show that a pronounced...

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Section: Discussionmentioning

confidence: 73%

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO₃substrates

et al. 2016

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“…Computational studies predicting the superconductivity in monolayer graphene [28,29] and phosphorene [30] were preceding the experimental observations [18,20,21]. Also, superconductivity at nonzero charge doping has already been predicted for recently proposed arsenene [31] (monolayer As), as well as for silicene [32].…”

Section: Introductionmentioning

confidence: 69%

Electron-phonon properties, structural stability, and superconductivity of doped antimonene

Lugovskoi¹,

Katsnelson

Руденко

2019

Phys. Rev. B

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Antimonene is a recently discovered two-dimensional semiconductor with exceptional environmental stability, high carrier mobility, and strong spin-orbit interactions. In combination with electric field, the latter provides an additional degree of control over the material's properties because of induced spin splitting. Here, we report on a computational study of electron-phonon coupling and superconductivity in n-and p-doped antimonene, where we pay a special attention on the effect of the perpendicular electric field. The range of accessible hole concentrations is significantly limited by the dynamical instability, associated with strong Fermi-surface nesting. At the same time, we find that in the case of electron-doping antimonene remains stable and can be turned into a state with strong electron-phonon coupling, with the mass enhancement factor λ of up to 2.3 at realistic charge carrier concentrations. In this regime, antimonene is expected to be a superconductor with the critical temperature of ≈16 K. Application of bias voltage leads to a considerable modification of the electronic structure, affecting the electron-phonon coupling in antimonene. While these effects are less obvious in the case of electron-doping, the field effect in hole-doped antimonene results in a considerable variation of the critical temperature, depending on bias voltage. arXiv:1806.08203v4 [cond-mat.supr-con]

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“…We have recently used this methodology to investigate the superconducting properties of layered and two-dimensional materials with highly anisotropic Fermi surfaces [36][37][38][39]. The electronic wavefunctions required for the Wannier-Fourier inarXiv:1703.03012v1 [cond-mat.supr-con] 8 Mar 2017…”

Section: Methodsmentioning

confidence: 99%

Electron-phonon coupling and pairing mechanism in β−Bi2Pd centrosymmetric superconductor

Zheng¹,

Margine²

2017

Phys. Rev. B

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We report first-principles calculations of the superconducting properties of β-Bi2Pd within the fully anisotropic Migdal-Eliashberg formalism. We find a single anisotropic superconducting gap of s-wave symmetry which varies in magnitude on the different regions of the Fermi surface. The calculated superconducting energy gap on the Fermi surface, the superconducting transition temperature, the specific heat, and the quasi-particle density of states are in good agreement with the corresponding experimental results and support the view that β-Bi2Pd is a phonon-mediated single anisotropic gap superconductor.

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Two-gap superconductivity in heavilyn-doped graphene:Ab initioMigdal-Eliashberg theory

Cited by 81 publications

References 77 publications

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO₃substrates

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO₃substrates

Electron-phonon properties, structural stability, and superconductivity of doped antimonene

Electron-phonon coupling and pairing mechanism in β−Bi2Pd centrosymmetric superconductor

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Two-gap superconductivity in heavilyn-doped graphene:Ab initioMigdal-Eliashberg theory

Cited by 81 publications

References 77 publications

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO3substrates

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO3substrates

Electron-phonon properties, structural stability, and superconductivity of doped antimonene

Electron-phonon coupling and pairing mechanism in β−Bi2Pd centrosymmetric superconductor

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Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO₃substrates

Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO₃substrates