Energy scales in 4f1 delafossite magnets: Crystal-field splittings larger than the strength of spin-orbit coupling in KCeO2

M. S. Eldeeb, T. Petersen, L. Hozoi, V. Yushankhai, and U. K. Rößler
Phys. Rev. Materials 4, 124001 – Published 4 December 2020; Erratum Phys. Rev. Materials 6, 029901 (2022)

Abstract

Ytterbium-based delafossites with effective S̃=1/2 moments are investigated intensively as candidates for quantum spin-liquid ground states. While the synthesis of related cerium compounds has also been reported, many important details concerning their crystal, electronic, and magnetic structures are unclear. Here we analyze the S̃=1/2 system KCeO2, combining complementary theoretical methods. The lattice geometry was optimized and the band structure investigated using density functional theory extended to the level of a GGA+U calculation in order to reproduce the correct insulating behavior. The Ce 4f1 states were then analyzed in more detail with the help of ab initio wave-function-based computations. Unusually large effective crystal-field splittings of up to 320 meV are predicted, which puts KCeO2 in the strong field coupling regime. Our results reveal a subtle interplay between ligand-cage electrostatics and the trigonal field generated by the extended crystalline surroundings, relevant in the context of recent studies on tuning the nature of the ground-state wave function in 4f triangular-lattice and pyrochlore compounds. It also makes KCeO2 an interesting model system in relation to the effect of large crystal-field splittings on the anisotropy of intersite exchange in spin-orbit coupled quantum magnets.

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  • Received 4 September 2020
  • Revised 29 October 2020
  • Accepted 17 November 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.124001

©2020 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Erratum

Authors & Affiliations

M. S. Eldeeb1, T. Petersen1, L. Hozoi1, V. Yushankhai2,3, and U. K. Rößler1

  • 1Institute for Theoretical Solid State Physics, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
  • 2Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Russia
  • 3Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzerstrasse 38, 01187 Dresden, Germany

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Vol. 4, Iss. 12 — December 2020

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