Stripe-yz magnetic order in the triangular-lattice antiferromagnet KCeS2. (10th August 2021)

• Record Type: Journal Article
• Authors: Kulbakov, Anton A; Avdoshenko, Stanislav M; Puente-Orench, Inés; Deeb, Mahmoud; Doerr, Mathias; Schlender, Philipp; Doert, Thomas; Inosov, Dmytro S
• Is Part Of: Journal of physics. Volume 33:Number 42(2021)
• Publication Date: 2021-08-10
• Subjects: triangular-lattice antiferromagnets -- spin liquids -- rare-earth magnetism -- f-electron systems -- rare-earth delafossites -- stripe-yz magnetic order -- magnetic anisotropy; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac15d6
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Yb- and Ce-based delafossites were recently identified as effective spin-1/2 antiferromagnets on the triangular lattice. Several Yb-based systems, such as NaYbO2, NaYbS2, and NaYbSe2, exhibit no long-range order down to the lowest measured temperatures and therefore serve as putative candidates for the realization of a quantum spin liquid. However, their isostructural Ce-based counterpart KCeS2 exhibits magnetic order below T N = 400 mK, which was so far identified only in thermodynamic measurements. Here we reveal the magnetic structure of this long-range ordered phase using magnetic neutron diffraction. We show that it represents the so-called 'stripe- yz ' type of antiferromagnetic order with spins lying approximately in the triangular-lattice planes orthogonal to the nearest-neighbor Ce–Ce bonds. No structural lattice distortions are revealed below T N, indicating that the triangular lattice of Ce 3+ ions remains geometrically perfect down to the lowest temperatures. We propose an effective Hamiltonian for KCeS2, based on a fit to the results of ab initio calculations, and demonstrate that its magnetic ground state matches the experimental spin structure.