Emergent Hyper-Magic Manifold in Twisted Kitaev Bilayers

Abstract

Kitaev quantum spin liquids have been the focus of intense research effort thanks to the discovery of various materials (e.g., RuCl3) that approximate their intriguing physics. In this paper we construct a mean-field approximation for a moirè superlattice emerging in twisted Kitaev bilayers in terms of solutions of commensurate bilayers. We show that the band structure of deconfined spinons, defined on the mini-Brillouin zone of the superlattice, is greatly modified. Bands which are almost perfectly flat appear at energies above the lowest gap. Including intralayer modulation, such bands become isolated from other dispersive ones. Intriguingly, flat-band eigenstates exhibit a localization akin to wavefunctions of Kagome lattices.