Phonon-mediated superconductivity in doped monolayer materials

Thingstad, Even; Kamra, Akashdeep; Wells, Justin W.; Sudbø, Asle

doi:10.1103/physrevb.101.214513

Cited by 20 publications

(14 citation statements)

References 70 publications

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“…The energy spectrum for electrons and phonons are shown in Fig. 5(a) and (b), respectively, which are consistent with the literature [59][60][61][62][63]. The parameters for the calculation of energy spectrum of electrons and phonons are summarized in table II.…”

Section: B Numerical Calculations Of Electron-phonon Interaction In A...supporting

confidence: 85%

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Electron-K-Phonon Interaction In Twisted Bilayer Graphene

Liu¹,

Chen²,

Yazdani³

et al. 2023

Preprint

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We develop an analytic theory to describe the interaction between electrons and K-phonons and study its influence on superconductivity in the bare bands of twisted bilayer graphene (TBG). We find that, due to symmetry and the two-center approximation, only one optical K phonon (∼ 160meV ) of graphene is responsible for inter-valley electron-phonon interaction. This phonon has recently been found in angular-resolved photo-emission spectroscopy to be responsible for replicas of the TBG flat bands. By projecting the interaction to the TBG flat bands, we perform the full symmetry analysis of phonon-mediated attractive interaction and pairing channels in the Chern basis, and show that several channels are guaranteed to have gapless order parameters. From the linearized gap equations, we find that the highest Tc pairing induced by this phonon is a singlet gapped s-wave inter-Chern-band order parameter, followed closely by a gapless nematic d-wave intra-Chern-band order parameter. We justify these results analytically, using the topological heavy fermion mapping of TBG which has allowed us to obtain an analytic form of phonon-mediated attractive interaction and to analytically solve the linearized and T = 0 gap equations. For the intra-Chern-band channel, the nematic state with nodes is shown to be stabilized in the chiral flat band limit. While the flat band Coulomb interaction can be screened sufficiently enough -around Van-Hove singularities -to allow for electron-phonon based superconductivity, it is unlikely that this effect can be maintained in the lower density of states excitation bands around the correlated insulator states.

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Section: B Numerical Calculations Of Electron-phonon Interaction In A...supporting

confidence: 85%

“…The resulting in-plane phonon dispersion in Fig. 1a reproduces that in literature [59][60][61][62][63] (SM Sec.III and IV.B [55]). The phonon modes at Γ and ηK D can induce intra-valley and inter-valley e-ph interactions, respectively.…”

supporting

confidence: 84%

Electron-K-Phonon Interaction In Twisted Bilayer Graphene

Liu¹,

Chen²,

Yazdani³

et al. 2023

Preprint

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“…57 Furthermore, a recent theoretical paper shows that for monolayer graphene, the main phonon mode involved in e-ph coupling in the p-band for moderate doping is one of the lower energy acoustic modes. 58 It appears that an informed design of new 2D materials, with the ultimate aim of achieving room temperature superconductivity, will require systematic measurements of l in the low energy phonon regime for a broad range of 2D material systems.…”

Section: The Electron-phonon Coupling Constant K In the Low Energy Rangementioning

confidence: 99%

Material properties particularly suited to be measured with helium scattering: selected examples from 2D materials, van der Waals heterostructures, glassy materials, catalytic substrates, topological insulators and superconducting radio frequency materials

Holst

Alexandrowicz

Avidor

et al. 2021

Phys. Chem. Chem. Phys.

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“…Hexagonal boron nitride (hBN) is an inert layered compound that has gained significant attention for its compatibility with the vast majority of low-dimensional van der Waals (vdW) materials. − It is strikingly similar to graphene in lateral size, crystalline structure, and Debye frequency, but due to its dissimilar sublattices, it hosts a wide energy band gap separating the valence and conduction bands. , For the engineering of vdW heterostructures embedded in the form of devices, hBN has proven to be a key building block due to its large capacitive coupling and current tunneling barrier. ,− Furthermore, its chemical inertness, large energy bandgap, and high phonon energies have made it one of the most common dielectrics for use in state-of-the-art, low-dimensional devices that require atomic-scale flatness and negligible interface doping and scattering. ,,− Recently, hBN has been predicted to host a strong electron–phonon coupling which can compromise the performance of hBN-derived electronic devices. , However, experimental proof of such couplings has so far been lacking. Herein, we investigate the many-body effects of few-layer hBN supported on graphene.…”

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confidence: 99%

Phonon-Mediated Quasiparticle Lifetime Renormalizations in Few-Layer Hexagonal Boron Nitride

et al. 2023

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Understanding the collective behavior of the quasiparticles in solid-state systems underpins the field of nonvolatile electronics, including the opportunity to control many-body effects for well-desired physical phenomena and their applications. Hexagonal boron nitride (hBN) is a wide-energy-bandgap semiconductor, showing immense potential as a platform for lowdimensional device heterostructures. It is an inert dielectric used for gated devices, having a negligible orbital hybridization when placed in contact with other systems. Despite its inertness, we discover a large electron mass enhancement in few-layer hBN affecting the lifetime of the π-band states. We show that the renormalization is phononmediated and consistent with both single-and multiple-phonon scattering events. Our findings thus unveil a so-far unknown manybody state in a wide-bandgap insulator, having important implications for devices using hBN as one of their building blocks.

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Phonon-mediated superconductivity in doped monolayer materials

Cited by 20 publications

References 70 publications

Electron-K-Phonon Interaction In Twisted Bilayer Graphene

Electron-K-Phonon Interaction In Twisted Bilayer Graphene

Material properties particularly suited to be measured with helium scattering: selected examples from 2D materials, van der Waals heterostructures, glassy materials, catalytic substrates, topological insulators and superconducting radio frequency materials

Phonon-Mediated Quasiparticle Lifetime Renormalizations in Few-Layer Hexagonal Boron Nitride

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