Superconductivity in octagraphene

Abstract

This article reviews the basic theoretical aspects of octagraphene, an one-atom-thick allotrope of carbon, with unusual two-dimensional (2D) Fermi nesting, hoping to contribute to the new family of quantum materials. Octagraphene has an almost strongest sp 2 hybrid bond similar to graphene, and has the similar electronic band structure as iron-based superconductors, which makes it possible to realize high-temperature superconductivity. We have compared various possible mechanisms of superconductivity, including the unconventional s ± superconductivity based on spin fluctuation and conventional superconductivity based on electron-phonon coupling. Theoretical studies have shown that octagraphene has relatively high structural stability. Although many 2D carbon materials with C 4 carbon ring and C 8 carbon ring structures have been reported, it is still challenging to realize the octagraphene with pure square-octagon structure experimentally. This material holds hope to realize new 2D high-temperature superconductivity.

Exceeding the Chandrasekhar-Clogston limit in flat-band superconductors: A multiband strong-coupling approach

“…Flat bands can appear in partial line graphs [23], e.g., realized in octagraphene [24][25][26][27], in twisted bilayers such as twisted-bilayer graphene [28][29][30][31][32][33], in rhombohedral graphite [34][35][36], in Lieb lattices [37][38][39][40], and in diatomic kagome lattices [41,42]. Often, the flat bands result from the interplay between several different hopping amplitudes in the nontrivial lattice structures.…”