Revisiting the magnetic responses of bilayer graphene from the perspective of the quantum distance

Fuente: arXiv
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Autores principales: Oh, Chang-geun, Rhim, Jun-Won, Yang, Bohm-Jung
Formato: Preprint
Publicado: 2024
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author Oh, Chang-geun
Rhim, Jun-Won
Yang, Bohm-Jung
author_facet Oh, Chang-geun
Rhim, Jun-Won
Yang, Bohm-Jung
contents We study the influence of the quantum geometry on the magnetic responses of quadratic band crossing semimetals. More explicitly, we examine the Landau levels, quantum Hall effect, and magnetic susceptibility of a general two-band Hamiltonian that has fixed isotropic quadratic band dispersion but with tunable quantum geometry, in which the interband coupling is fully characterized by the maximum quantum distance $d_\mathrm{max}$. By continuously tuning $d_\mathrm{max}$ in the range of $0\leq d_\mathrm{max}\leq 1$, we investigate how the magnetic properties of the free electron model with $d_\mathrm{max}=0$ evolve into those of the bilayer graphene with $d_\mathrm{max}=1$. We demonstrate that despite sharing the same energy dispersion $ε(p) =\pm\frac{p^2}{2m}$, the charge carriers in the free electron model and bilayer graphene exhibit entirely distinct Landau levels and quantum Hall responses due to the nontrivial quantum geometry of the wave functions.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05939
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Revisiting the magnetic responses of bilayer graphene from the perspective of the quantum distance
Oh, Chang-geun
Rhim, Jun-Won
Yang, Bohm-Jung
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
We study the influence of the quantum geometry on the magnetic responses of quadratic band crossing semimetals. More explicitly, we examine the Landau levels, quantum Hall effect, and magnetic susceptibility of a general two-band Hamiltonian that has fixed isotropic quadratic band dispersion but with tunable quantum geometry, in which the interband coupling is fully characterized by the maximum quantum distance $d_\mathrm{max}$. By continuously tuning $d_\mathrm{max}$ in the range of $0\leq d_\mathrm{max}\leq 1$, we investigate how the magnetic properties of the free electron model with $d_\mathrm{max}=0$ evolve into those of the bilayer graphene with $d_\mathrm{max}=1$. We demonstrate that despite sharing the same energy dispersion $ε(p) =\pm\frac{p^2}{2m}$, the charge carriers in the free electron model and bilayer graphene exhibit entirely distinct Landau levels and quantum Hall responses due to the nontrivial quantum geometry of the wave functions.
title Revisiting the magnetic responses of bilayer graphene from the perspective of the quantum distance
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2406.05939