SKM 2021 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Posters Magnetism IV
MA 15.38: Poster
Donnerstag, 30. September 2021, 13:30–16:30, P
Magnetic ordering/disordering in MnS and the effects of pressure on its structural landscape — •Artem Chmeruk1 and Maribel Núñez-Valdez1,2 — 1Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473, Potsdam — 2Goethe-Universität Frankfurt am Main, Altenhoeferallee 1 D-60438, Frankfurt a.M., Germany
We investigate magnetic ordering/disordering in MnS polymorphs and their pressure stability fields by applying density functional theory (DFT) in combination with special quasi-random structures (SQS) and occupational matrix control (OMC) algorithms to deal with the correlated Mn d-electrons. Departing from the experimentally known low temperature antiferromagnetic (AFM) ordering in different MnS polymorphs, we evaluate their energy stability and compare to experimental observations. Then to simulate their paramagnetic (PM) state above Néel temperature, we construct their SQS supercells of randomly distributed up ↑ and down ↓ local Mn magnetic moments. Our calculated enthalpy landscape indicates that, the RS polymorph remains the most stable phase at 0 GPa, but as pressure increases, it undergoes a structural transformation to an orthorhombic MnP-type structure at about 21 GPa. The identification of this pressure-induced phase transition sheds light onto the nature of an unknown phase previously reported at ∼26 GPa from high-pressure diamond-anvil-cell experiments. In general, we show that our methodology provides accurate magnitudes of structural parameters, energy band gaps, and local magnetic moments and it could be extended to the study of other transition metal sulphides.