Dresden 2020 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 22: Frustrated Magnets - Spin Liquids 1 (joint session TT/MA)

MA 22.6: Vortrag

Dienstag, 17. März 2020, 10:45–11:00, HSZ 304

DFT calculations of the quantum spin liquid candidate Na₂BaCo(PO₄)₂ — •Willi Roscher, Christoph Wellm, Bernd Büchner, Vladislav Kataev, and Oleg Janson — Leibniz Institute for Solid State and Materials Research Dresden, Germany

The recently synthesized triangular lattice magnet Na₂BaCo(PO₄)₂ shows effective S=1/2 behavior with strong quantum fluctuations persistent down to 50 mK, rendering it as a candidate for the quantum spin liquid (QSL) ground state [1,2]. Very recent ESR and magnetization measurements hint at a more complex picture with different energy scales. To provide a microscopic insight, we perform band structure DFT calculations using the full-potential code FPLO. We calculate the band structure and Wannier projections for the t_2g an e_g states of Co. The evaluated transfer integrals are used to estimate the leading magnetic exchanges, the spin orbit coupling constant and the trigonal crystal field splitting. These two latter parameters are used to assess the electronic ground state and the excitation spectrum of Co²⁺ atoms. Finally, we compare our theoretical findings with new experimental studies.

[1] R. Zhong et al., Proc. Natl. Acad. Sci., 116, pp. 14505-14510 (2019)

[2] N. Li et al., arXiv:1911.11107 (2019)