Superconducting Phases In Lithium Decorated Graphene Lic6

Abstract

A study of possible superconducting phases of graphene has been constructed in detail. A realistic tight binding model, fit to ab initio calculations, accounts for the Li-decoration of graphene with broken lattice symmetry, and includes s and d symmetry Bloch character that influences the gap symmetries that can arise. The resulting seven hybridized Li-C orbitals that support nine possible bond pairing amplitudes. The gap equation is solved for all possible gap symmetries. One band is weakly dispersive near the Fermi energy along Γ → M where its Bloch wave function has linear combination of dx2−y2 and dxy character, and is responsible for dx2−y2 and dxy pairing with lowest pairing energy in our model. These symmetries almost preserve properties from a two band model of pristine graphene. Another part of this band, along K → Γ, is nearly degenerate with upper s band that favors extended s wave pairing which is not found in two band model. Upon electron doping to a critical chemical potential μ1 = 0.22 eV the pairing potential decreases, then increases until a second critical value μ2 = 1.3 eV at which a phase transition to a distorted s-wave occurs. The distortion of d- or s-wave phases are a consequence of decoration which is not appear in two band pristine model. In the pristine graphene these phases convert to usual d-wave or extended s-wave pairing.

Publication Date

12-1-2018

Publication Title

Scientific Reports

Volume

8

Issue

1

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1038/s41598-018-32050-9

Socpus ID

85053356067 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85053356067

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