X-ray diffraction and spectroscopy studies under high pressure to clarify possible quantum spin-liquid states in Na3Co2SbO6

Abstract

Honeycomb cobaltates with Co²⁺ (3d⁷) ions have been proposed as materials which can host Kitaev quantum spin-liquid (QSL) states. Specifically, Na₃Co₂SbO₆ has been predicted to exhibit a Kitaev QSL upon reduction of the trigonal ligand- and crystal-field splitting, which in turn might be possible via the elastic tuning of the lattice structure [1,2]. This compound hosts edge-sharing CoO₆ octahedra and exhibits antiferromagnetic zig-zag ordering below 8 K [3]. In this talk, I present a combination of x-ray diffraction (XRD) and spectroscopy (NIXS) in diamond anvil cells to explore the effect of hydrostatic pressure on the lattice and electronic structure of Na₃Co₂SbO₆. While XRD reveals the pressure dependence of the lattice structure, the high-pressure Co L edge dependence is probed by NIXS, yielding information about the pressure dependent configuration of the Co 3d shell. I present crystal structure data up to 17 GPa of the C2/m monoclinic structure. The NIXS results show significant changes of the Co L-edge line shape for hydrostatic pressures up to 5 GPa. This sets the basis for upcoming theoretical modeling with multiplet and density-functional calculations. 

[1] Liu, Huimei, et al., Phys. Rev. Lett. 15, 047201 (2020).
[2] Liu, Huimei, et al., Phys. Rev. B 97, 014407 (2018).
[3] Yan, J.-Q., et al., Phys. Rev. Mater. 3, 074405 (2019).

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