Magnon Landau levels in the strained antiferromagnetic honeycomb nanoribbons

The pseudomagnetic field created by a nonuniform uniaxial strain is introduced into the antiferromagnetic honeycomb nanoribbons. The formation of magnon pseudo-Landau levels, which appear from the upper end of the spectrum and whose level spacings are proportional to the square root of the level index, is revealed by the linear spin-wave theory. The antiferromagnetic order is gradually weakened along the y-direction by the strain. At large enough strength, the system is decoupled into isolated zigzag chains near the upper boundary and demonstrates one-dimensional magnetic property there. While the quantum Monte Carlo simulations also predict such a transition, this exact method gives a critical point deeper in the bulk. We also investigate the XY antiferromagnetic honeycomb nanoribbons and find similar pseudo-Landau levels and antiferromagnetic evolution. Our results unveil the effect of a nonuniform uniaxial strain on the spin excitations and may be realized experimentally based on two-dimensional quantum magnetic materials.