Year: 2025
Type: article
Abstract: The lowest Landau level of bilayer graphene has an octet of internal degrees of freedom, composed from spin, valley, and orbital two-level systems. Dominance of n=0 orbitals over n=1 orbitals in low energy quantum fluctuations leads to distinct fractional quantum Hall characteristics compared dominance of n=1 over n=0. The competition between n=0 and n=1 orbitals depends sensitively on particle-hole asymmetry in the single-particle Hamiltonian and on Lamb shifts due to exchange interactions with the negative energy sea, which must be accounted for simultaneously in assessing the orbital competition. We identify the circumstances under which n=1, which supports strong even-denominator fractional quantum Hall states with non-Abelian quasiparticles, emerges robustly as the low-energy Landau level.
Source: Physical Review Letters
Authors: Bishoy M. Kousa, Nemin Wei, Allan H. MacDonald
Institutions: The University of Texas at Austin, Yale University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: Simons Foundation, Welch Foundation
Awards: G6498847258, G6765329077
OpenAlex ID: W4407956633