Regensburg 2025 – scientific programme
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MA: Fachverband Magnetismus
MA 47: Altermagnets III
MA 47.4: Talk
Friday, March 21, 2025, 10:15–10:30, H20
A Heisenberg model for g-wave altermagnets: the comparative analysis of CrSb and MnTe — •Volodymyr Kravchuk1,2, Kostiantyn Yershov1,2, Oleg Janson1, and Jeroen van den Brink1 — 1Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany — 2Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine, 03143 Kyiv, Ukraine
Here we construct a discrete Hamiltonian of the magnetic subsystem of altermagnets belonging to the crystallographic group 6/mmm. The altermagnetic properties are captured through the additional Heisenberg exchange interactions whose symmetry respects the positions of the nonmagnetic atoms. We derive the dispersion relation for magnons for two opposite cases of magnetocrystalline anisotropy: easy-axis (as for CrSb) and easy-plane (as for MnTe). Due to the different magnetic ground states of CrSb and MnTe, their magnon spectra are drastically different. While the splitting of the magnon bands of CrSb possesses the g-wave symmetry, the splitting of the magnon bands of MnTe does not alternate sign within the Brillouin zone and does not possess g-wave symmetry. We formulate the continuous approximation of the model and derive the expression for magnetization of the noncollinear magnetization structures. We find that the amplitude of the magnetization of a domain wall in CrSb depends on the domain wall orientation relative to crystallographic axes, and determine twelve orientations that correspond to the maximal magnetization.
Keywords: g-wave altermagnetism; magnon spectra; domain wall