The role of correlated hopping in many-body physics of flat-band systems: Nagaoka ferromagnetism

Abstract

In narrow-band systems, correlated contribution to effective hopping becomes important, and one needs to carefully consider three types of hopping processes: between doubly and singly occupied sites, between singly occupied and empty sites, and between doubly occupied and empty or two singly occupied sites. All three hopping parameters cannot vanish simultaneously, and one should specify for which of these processes the band becomes flat. By means of exact diagonalization of finite systems we demonstrate that three hoppings play qualitatively different roles in many-body effects, in particular, in the formation of half-metallic ferromagnetic (Nagaoka) states.

v3: minor corrections after acceptance for publication; v2: fix definitions of hoppings, update figures, add connection to real materials; v1: 5 pages, 1 figure in the main text, 1 figure in the supplemental information

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Cited by in corpus (4)

• Polaronic mechanism of Nagaoka ferromagnetism in Hubbard models
• Jordan-Wigner transformation constructed for spinful fermions at S=1/2 spins in one dimension
• Signatures of the Correlated-Hopping Interaction in Non-Linear Transport through a Quantum Dot
• Spin-1/2 operators exactly mapped to spinful canonical Fermi operators present in two bands