Vacancy-Engineered Flat-Band Superconductivity in Holey Graphene

Abstract

A bipartite lattice with chiral symmetry is known to host zero energy flat bands if the numbers of the two sublattices are different. We demonstrate that this mechanism of producing flat bands can be realized on graphene by introducing periodic vacancies. Using first-principle calculations, we elaborate that even though the pristine graphene does not exactly preserve chiral symmetry, this mechanism applied to holey graphene still produces single or multiple bands as narrow as ∼ 0.5eV near the Fermi surface throughout the entire Brillouin zone. Moreover, this mechanism can combine with vacancy-engineered nonsymmorphic symmetry to produce band structures with coexisting flat bands and nodal lines. A weak coupling mean-field treatment suggests the stabilization of superconductivity by these vacancy-engineered narrow bands. In addition, superconductivity occurs predominantly on the majority sublattices, with an amplitude that increases with the number of narrow bands.

Ferromagnetism in armchair graphene nanoribbon heterostructures

“…Indeed, in the last one year alone, there has been new flatband research in many different areas, like their experimental observation in atomically precise one-dimensional (1D) chains [7], as well as the study of flat-bands in strongly correlated systems [8][9][10][11][12][13][14][15][16], search for flat-bands in kagome-type lattices [17,18], study of symmetry aspects of flat-band systems [19][20][21], holographic construction of flat-bands [22], flat-bands in pyrochlore lattices [23,24], analysis of randomness in flat-band Hamiltonians [25], topological aspects of flat-band systems [26][27][28][29][30][31], construction of flat-band tightbinding models starting from compact localized states [32], and study of flat-bands in graphene and graphene-like lattices [33][34][35][36][37].…”