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

TL;DR

This paper investigates how the degeneracy and sublattice polarization of pseudo-Landau levels in strained honeycomb lattices depend on geometry, revealing algebraic constraints that differ from traditional magnetic Landau level behavior.

Contribution

It uncovers geometry-dependent degeneracy doubling and sublattice polarization in pseudo-Landau levels, highlighting algebraic constraints distinct from magnetic field effects.

Findings

0th pLL shows doubled degeneracy in hexagonal and rectangular flakes

Sublattice polarization of 0th pLL varies with geometry, fully realized only in zigzag-terminated triangles

Features are governed by algebraic constraints in atomistic theory

Abstract

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 0th pLL displays a twofold increased degeneracy, while the characteristic sublattice polarization of the 0th 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.