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  • Letter
  • Open Access

Quantum topological phase transitions in skyrmion crystals

Kristian Mæland and Asle Sudbø*

  • Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway

  • *Corresponding author: asle.sudbo@ntnu.no

Phys. Rev. Research 4, L032025 – Published 12 August, 2022

DOI: https://doi.org/10.1103/PhysRevResearch.4.L032025

Abstract

Topological order is important in many aspects of condensed matter physics and has been extended to bosonic systems. In this Letter we report on the nontrivial topology of the magnon bands in two distinct quantum skyrmion crystals appearing in zero external magnetic field. This is revealed by nonzero Chern numbers for some of the bands. As a bosonic analog of the quantum anomalous Hall effect, we show that topological magnons can appear in skyrmion crystals without explicitly breaking time-reversal symmetry with an external magnetic field. By tuning the value of the easy-axis anisotropy at zero temperature, we find eight quantum topological phase transitions signaled by discontinuous jumps in certain Chern numbers. We connect these quantum topological phase transitions to gaps closing and reopening between magnon bands.

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