Kondo-lattice-mediated interactions in flat band systems

Abstract

Electronic flat bands represent a paradigmatic platform to realize strongly correlated matter due to their associated divergent density of states. In common instances, including electron-electron interactions leads to magnetic instabilities for repulsive interactions and superconductivity for attractive interactions. Nevertheless, interactions of Kondo nature in flat band systems have remained relatively unexplored. Here we address the emergence of interacting states mediated by Kondo lattice coupled to a flat band system. Combining dynamical mean-field theory and tensor networks methods to solve flat band Kondo lattice models in one and two dimensions, we show the emergence of a robust underscreened regime leading to a magnetically ordered state in the flat band. Our results put forward flat band Kondo lattice models as a platform to explore the genuine interplay between flat band physics and many-body Kondo screening.

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].…”