Degeneracy doubling and sublattice polarization in strain-induced pseudo-Landau levels

The degeneracy and spatial support of pseudo-Landau levels (pLLs) in strained honeycomb lattices systematically depends on the geometry; for instance, in hexagonal and rectangular flakes the zeroth pLL displays a twofold increased degeneracy, while the characteristic sublattice polarization of the zeroth pLL is only fully realized in a zigzag-terminated triangle. These features are dictated by algebraic constraints in the atomistic theory and signify a departure from the standard picture in which all qualitative differences between pLLs and Landau levels induced by a magnetic field trace back to the valley antisymmetry of the pseudomagnetic field.