Revisiting the magnetic responses of bilayer graphene from the perspective of quantum distance
Year: 2024
Type: article
Abstract: We study the influence of 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 $0\ensuremath{\le}{d}_{\mathrm{max}}\ensuremath{\le}1$, 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 $\ensuremath{\epsilon}(\mathbit{p})=\ifmmode\pm\else\textpm\fi{}\frac{{p}^{2}}{2m}$, 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.
Authors: Chang-geun Oh, Jun-Won Rhim, Bohm-Jung Yang
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4403187440