The Quantum Hall ferroelectric helix in bilayer graphene

Thierry Jolicoeur (1) , Csaba Tőke , Inti Sodemann (2)

1 IPHT - Institut de Physique Théorique - UMR CNRS 3681
2 University of Texas at Austin [Austin]

We reexamine the nature of the ground states of bilayer graphene at odd integer filling factors within a simplified model of nearly degenerate n = 0 and n = 1 Landau levels. Previous Hartree-Fock studies have found that ferroelectric states with orbital coherence can be stabilized by tuning the orbital splitting between these levels. These studies indicated that, in addition to a uniform ferroelectric state, a helical ferroelectric phase with spontaneously broken translational symmetry is possible. By performing exact diagonalization on the torus, we argue that the system does not have a uniform coherent state but instead transitions directly from the uniform incoherent state into the ferroelectric helical phase. We argue that there is a realistic prospect to stabilize the helical ferroelectric state in bilayer graphene by tuning the interlayer electric field in a model that includes all single particle corrections to its zero energy eight-fold multiplet of Landau levels.

Domaines: Autre [cond-mat.other]

Thierry Jolicoeur, Csaba Tőke, Inti Sodemann. The Quantum Hall ferroelectric helix in bilayer graphene. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2019, 99 (11), ⟨10.1103/PhysRevB.99.115139⟩. ⟨hal-02123104⟩