Magnon topology driven by altermagnetism

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • Subhankar Khatua - , Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Würzburg-Dresden Cluster of Excellence ctd.qmat (Autor:in)
  • Volodymyr P. Kravchuk - , Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, NASU - Bogolyubov Institute for Theoretical Physics, Würzburg-Dresden Cluster of Excellence ctd.qmat (Autor:in)
  • Kostiantyn V. Yershov - , Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, NASU - Bogolyubov Institute for Theoretical Physics (Autor:in)
  • Jeroen van den Brink - , Exzellenzcluster ctd.qmat: Complexity, Topology and Dynamics in Quantum Matter, Professur für Festkörpertheorie (gB/IFW), Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (Autor:in)

Abstract

Altermagnets present a class of fully compensated collinear magnetic order, where the two sublattices are not related merely by time-reversal combined with lattice translation or inversion, but require an additional lattice rotation. This distinctive symmetry leads to a characteristic splitting of the magnon bands; however, the splitting is only partial—residual degeneracies persist along certain lines in the Brillouin zone as a consequence of the underlying altermagnetic rotation. We consider a two-dimensional d-wave altermagnetic spin model on the checkerboard lattice and introduce additional interactions such as an external magnetic field and Dzyaloshinskii-Moriya interactions that lift these degeneracies. The resulting magnon bands become fully gapped and acquire nontrivial topology, characterized by nonzero Chern numbers. We demonstrate the crucial role of altermagnetism for the generation of the Berry curvature. As a direct consequence of the topological magnons, we find finite thermal Hall conductivity κxy, which exhibits a characteristic low-temperature scaling, κxy ∝ T4. Moreover, κxy changes signs under reversal of the magnetic field, exhibiting a sharp jump across zero field at low temperatures. We also demonstrate topologically protected chiral edge modes in a finite strip geometry.

Details

OriginalspracheEnglisch
Aufsatznummer214422
Seitenumfang16
FachzeitschriftPhysical Review B
Jahrgang112
Ausgabenummer21
PublikationsstatusVeröffentlicht - 10 Dez. 2025
Peer-Review-StatusJa