SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 21: Correlated Electrons: Electronic Structure Calculations
TT 21.8: Talk
Tuesday, March 28, 2023, 11:15–11:30, HSZ 201
Quantum chemical study on cobalt(II) in honeycomb lattices based on multi-configurational approaches — •Thorben Petersen and Liviu Hozoi — Leibniz IFW Dresden, 01069 Dresden, Germany
Quantum Spin Liquids (QSLs) are fascinating materials that display quantum entanglement and host unconventional fractionated excitations. While QSL behavior was found in Cu(II) 3d9 cuprates, 4d5 RuCl3, 5d5 iridates and triangular-lattice 4f13 oxides, we here explore 3d7 Co(II) compounds such as Na2Co2TeO6, which form spin-orbit-entangled Jeff=1/2 pseudo-spin moments at Co(II) sites that potentially realize Kitaev-magnetism. In this study, we apply multi-configurational quantum-chemistry methods like CASSCF and beyond to model the t2g5 eg2 magnetic sites in these honeycomb oxides by carefully designing an embedded cluster model to represent the extended bulk lattice. With this, we quantify the extent of the 3d-site multiplet structure and spin-orbit coupling associated with the 4T2g ground state term. Moreover, our model will be validated against experimental magnetization data and first impressions on the 3d7-3d7 intersite couplings will be given.