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.

arXiv commentv3: 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

References in corpus (33)

• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
• Moire bands in twisted double-layer graphene
• Tuning superconductivity in twisted bilayer graphene
• Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene
• Observation of Van Hove singularities in twisted graphene layers
• Flat Bands in Slightly Twisted Bilayer Graphene
• From Nagaoka's ferromagnetism to flat-band ferromagnetism and beyond: An introduction to ferromagnetism in the Hubbard model
• Ferromagnetism in the Hubbard Model-- Examples from Models with Degenerate Single-Electron Ground States
• QuSpin: a Python Package for Dynamics and Exact Diagonalisation of Quantum Many Body Systems. Part II: bosons, fermions and higher spins
• Optimal Hubbard models for materials with nonlocal Coulomb interactions: graphene, silicene and benzene
• Quantum Hall Physics - hierarchies and CFT techniques
• Nagaoka ferromagnetism observed in a quantum dot plaquette
• Flat-Band Ferromagnetism as a Pauli-Correlated Percolation Problem
• Lattice dependence of saturated ferromagnetism in the Hubbard model
• Non-perturbative approaches to magnetism in strongly correlated electron systems
• Ferromagnetism in single-band Hubbard models with a partially flat band
• Quantum simulation of correlated-hopping models with fermions in optical lattices
• Flat-band ferromagnetism in quantum dot superlattices
• Ferromagnetism in Hubbard Models: Low Density Route
• Strong electron-phonon coupling and its influence on the transport and optical properties of hole-doped single-layer InSe
• Coexisting charge density wave and ferromagnetic instabilities in monolayer InSe
• Anomalous flux quantization in a Hubbard ring with correlated hopping
• Phase Diagrams from Topological Transitions: The Hubbard Chain with Correlated Hopping
• Magnetic polaron and antiferro-ferromagnetic transition in doped bilayer CrI${}_3$
• Random Phase Approximation for gapped systems: role of vertex corrections and applicability of the constrained random phase approximation
• Density-of-states picture and stability of ferromagnetism in the highly-correlated Hubbard model
• Pairing Correlations in a Generalized Hubbard Model for the Cuprates
• Exact single spin flip for the Hubbard model in $d=\infty$
• Correlated-Electron Theory of Strongly Anisotropic Metamagnets
• On the derivation of the t-J model: electron spectrum and exchange interactions in narrow energy bands
• Electron self-trapping at quantum and classical critical points
• Electron self-trapping and fluctuation density-of-states tail at the critical point

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