Multi-orbital physics of edge-magnetism in a Hubbard model of transition-metal dichalcogenide nanoribbons: Comparing Mean Field Theory and Determinant Quantum Monte Carlo

Brito, Francisco M. O.; Castro, Eduardo V.; Lopes, J. M. Viana Parente

doi:10.1051/epjconf/202023303003

Cited by 1 publication

(1 citation statement)

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“…The effective Hubbard model for monolayer graphene with on-site interaction

was proposed [ 23 ], suggesting that large isotropic strain may drive this system from semimetallic towards the Mott-insulating phase [ 24 , 25 ] in analogy with high pressure changing properties of various bulk materials [ 26 , 27 , 28 , 29 , 30 ]. The effects of electron correlations are usually more pronounced in graphene nanosystems, where quantum fluctuations are reduced and magnetic moments may form near free edges [ 31 , 32 , 33 ] (although defining metallic and insulating states for a nanosystem is more cumbersome than for a bulk system [ 34 , 35 ]). We further notice that artificial graphene-like systems allow one to tune the interaction in a wider range than actual graphene [ 36 , 37 , 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Mott Transition in the Hubbard Model on Anisotropic Honeycomb Lattice with Implications for Strained Graphene: Gutzwiller Variational Study

Rut

Fidrysiak

Goc-Jagło

et al. 2023

IJMS

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The modification of interatomic distances due to high pressure leads to exotic phenomena, including metallicity, superconductivity and magnetism, observed in materials not showing such properties in normal conditions. In two-dimensional crystals, such as graphene, atomic bond lengths can be modified by more than 10 percent by applying in-plane strain, i.e., without generating high pressure in the bulk. In this work, we study the strain-induced Mott transition on a honeycomb lattice by using computationally inexpensive techniques, including the Gutzwiller Wave Function (GWF) and different variants of Gutzwiller Approximation (GA), obtaining the lower and upper bounds for the critical Hubbard repulsion (U) of electrons. For uniaxial strain in the armchair direction, the band gap is absent, and electron correlations play a dominant role. A significant reduction in the critical Hubbard U is predicted. Model considerations are mapped onto the tight-binding Hamiltonian for monolayer graphene by the auxiliary Su–Schrieffer–Heeger model for acoustic phonons, assuming zero stress in the direction perpendicular to the strain applied. Our results suggest that graphene, although staying in the semimetallic phase even for extremely high uniaxial strains, may show measurable signatures of electron correlations, such as the band narrowing and the reduction in double occupancies.

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“…The effective Hubbard model for monolayer graphene with on-site interaction