SKM 2023 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 34: Focus Session: Spin-Phonon Coupling

MA 34.8: Vortrag

Donnerstag, 30. März 2023, 12:45–13:00, HSZ 02

Magnetic ordering and spin-lattice interactions in MCrO₂ and MCrS₂ (with M = Li, Na, K, Cu, Ag, Au) — •S. Mankovsky, H. Lange, S. Polesya, and H. Ebert — Department Chemie, Ludwig Maximilian University, Munich, Germany

The triangular lattice antiferromagnets (TLA) are discussed in the literature as materials exhibiting a variety of magneto-elastic and magneto-electric properties determined by a complex magnetic structure driven by magnetic frustrations. In the present work we have investigated two groups of TLA compounds, MCrO₂ and MCrS₂, with M = Li, Na, K, Cu, Ag, Au. Their properties are discussed on the basis of first-principles calculations of their electronic structure as well as exchange coupling and spin-lattice coupling (SLC) parameters. The properties of these two groups are expected to be quite different, among others, because of a different distance dependency of the Cr-Cr exchange interactions. In particular one finds that the Cr layers in MCrS₂ cannot be treated as independent, in contrast to MCrSO₂ with quasi-2D frustrated AFM Cr layers. We discuss different contributions to the magnon-phonon interaction responsible for a modification of the phonon spectra in these materials, as well as a transition to the AFM state in some of them, accompanied by a lattice distortion as observed by experiment. In addition, a contribution of the inverse Dzyaloshinskii-Moriya (DM) interaction mechanism [PRL 95, 057205 (2005)] to the ferroelectric properties driven by the magnetic ordering is discussed on the basis of the calculated DM-SLC parameters.