Berlin 2024 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 46: Poster II
MA 46.40: Poster
Donnerstag, 21. März 2024, 15:00–18:00, Poster C
Thermodynamic properties of the checkerboard model of altermagnet — •Kostiantyn Yershov1,2, Volodymyr Kravchuk1,2, and Jeroen van den Brink1 — 1Leibniz Institute for Solid State and Materials Research, Dresden, Germany — 2Bogolyubov Institute for Theoretical Physics, Kyiv, Ukraine
Using the checkerboard Hubbard hamiltonian as a model for two-dimensional altermagnet, we demonstrated that the temperature-induced fluctuations can lead to several new effects, namely the fluctuation induced piezomagnetism and thermal spin conductivity. First, computing the dispersion relation for magnons, we demonstrated that the model under consideration breaks the spin degeneracy in the momentum space leading to the anisotropic splitting of magnon branches typical for the altermagnets. Next, in the limit of low temperatures we considered the thermally induced magnons as an ideal Bose gas and computed the thermodynamic potential accordingly. Using the thermodynamic potential, we computed magnetization M as a thermodynamic quantity, and demonstrated that M vanishes for vanishing magnetic field. However, M is finite beyond the altermagnetic limit, when the diagonal terms in the checkerboard model becomes not equivalent, e.g. due to the applied mechanical stress. In addition, we predict generation of the spin-current in the response to the applied temperature gradients. We calculated the tensor of thermal spin conductivity, which is linear with diagonal terms of checkerboard model for small temperatures.