Speakers
Dr
Laura Classen
(Max Planck Institute for Solid State Research)
Nikolaos Parthenios
(MSFK)
Description
A multitude of novel phases have been proposed for twisted bilayer graphene (TBG) at charge neutrality such as a nematic insulator which breaks C3 lattice symmetry or as inter-valley coherent order (IVC) which breaks U(1) valley symmetry. We show that the Dirac fermion model of TBG is invariant under an SU(4) group composed of combined spin, valley and sublattice transformations. We determine all symmetry-allowed four-fermion interactions and employ a renormalization group treatment to derive the flow equations for each of the six allowed couplings. We identify the critical points that describe transitions into the different ordered phases and discuss the corresponding critical behavior of the system.
Primary authors
Dr
Laura Classen
(Max Planck Institute for Solid State Research)
Nikolaos Parthenios
(MSFK)
