Magnon Landau levels in the strained antiferromagnetic honeycomb nanoribbons

TL;DR

This paper demonstrates the formation of magnon pseudo-Landau levels in strained antiferromagnetic honeycomb nanoribbons, revealing strain-induced magnetic phase transitions and potential experimental realizations in 2D quantum magnetic materials.

Contribution

It introduces the concept of magnon pseudo-Landau levels in strained antiferromagnetic nanoribbons and analyzes their properties using linear spin-wave theory and quantum Monte Carlo simulations.

Findings

Magnon pseudo-Landau levels form under non-uniform unaxial strain.

Strain weakens antiferromagnetic order, leading to a transition to 1D magnetic behavior.

Quantum Monte Carlo confirms the transition and predicts a deeper critical point.

Abstract

The pseudo-magnetic field created by a non-uniform unaxial 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 non-uniform unaxial strain on the spin excitaions, and may be realized experimentally based on two-dimensional quantum magnetic materials.