Poster

Interaction-Enhanced Topological Hall Effects in Strained Twisted Bilayer Graphene

Avatar

Avatar
user

What is this paper about?

AI: This paper is about the effects of long-range Coulomb interactions on the distribution of Berry curvature among the bands of twisted bilayer graphene closely aligned with hexagonal boron nitride. It analyzes how electron-electron interactions strongly renormalize the band structure and affect topological properties of the bands at certain fillings. The paper calculates linear and nonlinear Hall conductivities and finds that remote bands can contribute substantially to Hall currents while the contribution from central bands may be suppressed, particularly near regions of energies where the bands are highly entangled with each other. The results demonstrate how topological transport in TBG/hBN is substantially modified by electron-electron interactions and offer a simple explanation for recent experimental results.
Avatar
user

What is this paper about

AI: This paper analyzes the effects of long-range Coulomb interaction on the distribution of Berry curvature in twisted bilayer graphene (TBG) aligned with hexagonal boron nitride (hBN) and how electron-electron interactions modify the topological transport in TBG/hBN. The authors use a Hartree formalism to calculate linear and nonlinear Hall conductivities and find that for certain fillings, the remote bands contribute substantially to the Hall currents, while the contribution from the central bands is suppressed. Their results demonstrate that electron-electron interactions offer a simple explanation for recent experimental results.
Avatar
user

What is the technique they used?

AI: The technique used in this study is a Hartree formalism.

Authors

Pierre A. Pantaleón, Vo Tien Phong, Gerardo G. Naumis, Francisco Guinea

Abstract

We analyze the effects of the long-range Coulomb interaction on the distribution of Berry curvature among the bands near charge neutrality of twisted bilayer graphene (TBG) closely aligned with hexagonal boron nitride (hBN). Due to the suppressed dispersion of the narrow bands, the band structure is strongly renormalized by electron-electron interactions, and thus, the associated topological properties of the bands are sensitive to filling. Using a Hartree formalism, we calculate the linear and nonlinear Hall conductivities, and find that for certain fillings, the remote bands contribute substantially to the Hall currents while the contribution from the central bands is suppressed. In particular, we find that these currents are generically substantial near regions of energies where the bands are highly entangled with each other, often featuring doping-induced band inversions. Our results demonstrate that topological transport in TBG/hBN is substantially modified by electron-electron interactions, which offer a simple explanation to recent experimental results.

0 comments

Recommended SciCasts
Quantum chemistry on quantum annealers