Systematic extraction of crystal electric-field effects and quantum magnetic model parameters in triangular rare-earth magnets

Abstract

A primary goal at the interface of theoretical and experimental quantum magnetism is the investigation of exotic spin states, most notably quantum spin liquids (QSLs). Magnetic rare-earth ions go beyond the straightforward paradigm of geometrical frustration in Heisenberg antiferromagnets by introducing competing energy scales, and in particular their strong spin-orbit coupling creates multiple split crystal electric-field (CEF) levels, leading to anisotropic effective spin models with intrinsic frustration. While rare-earth delafossites have a triangular-lattice geometry, and thus have gained recent attention as candidates for hosting spin-1/2 QSL physics, the reliable extraction of effective spin models from the initial many-parameter CEF spectrum is a hard problem. Using the example of CsYbSe2, we demonstrate the unambiguous extraction of the Stevens-operators coefficients dictating the full CEF spectrum of Yb${}^{3+}$ by translating these into parameters with a direct physical interpretation. Specifically, we combine low-field susceptibility measurements with resonant torsion magnetometry experiments in fields up to 60 T to determine a sufficiently large number of physical parameters -- effective Zeeman splittings, anisotropic van Vleck coefficients, and magnetotropic coefficients -- that the set of Stevens-operator coefficients is unique. Our crucial identification of the strong corrections to the Zeeman splitting of Kramers doublets as van Vleck coefficients has direct consequences for the interpretation of all anisotropic magnetic susceptibility measurements. Our results allow us to determine the nature and validity of an effective spin-1/2 model for CsYbSe2, to provide input for theoretical studies of such models on the triangular lattice, and to provide additional materials insight into routes for achieving magnetic frustration and candidate QSL systems in rare-earth compounds.

17 pages, 7 figures

References in corpus (19)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
• $\alpha$-RuCl3: a Spin-Orbit Assisted Mott Insulator on a Honeycomb Lattice
• Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4
• Spin liquid phase of the $S=\frac{1}{2}$ $J_1-J_2$ Heisenberg model on the triangular lattice
• Unusual ordered phases of highly frustrated magnets: a review
• Crystalline Electric Field Randomness in the Triangular Lattice Spin-Liquid YbMgGaO${}_4$
• Anisotropic field-induced ordering in the triangular-lattice quantum spin liquid NaYbSe${}_2$
• Field-induced instability of the quantum-spin-liquid ground state in the $J_{\mathrm{eff}}=\frac{1}{2}$ triangular-lattice compound NaYbO${}_2$
• Quantum Spin Ice Dynamics in the Dipole-Octupole Pyrochlore Magnet Ce${}_2$Zr${}_2$O${}_7$
• Magnetic orders and topological phases from f-d exchange in pyrochlore iridates
• Quantum spin liquid ground state in the disorder free triangular lattice NaYbS${}_2$
• Symmetry Enriched U(1) Topological Orders for Dipole-Octupole Doublets on a Pyrochlore Lattice
• Field-induced magnetic transition and spin fluctuation in quantum spin liquid candidate CsYbSe${}_2$
• A Class of Compounds Featuring Frustrated Triangular Magnetic Lattice CsRESe${}_2$ (RE=La-Lu): Quantum Spin-Liquid Candidates
• Spin excitations in the frustrated triangular lattice antiferromagnet NaYbO${}_2$
• Magnetic Phase Diagram of the S=1/2 Triangular-Lattice Heisenberg Antiferromagnet Ba3CoNb2O9
• Ground States of Spin-1/2 Triangular Antiferromagnets in a Magnetic Field
• Yb delafossites: unique exchange frustration of 4f spin 1/2 moments on a perfect triangular lattice

Cited by in corpus (12)

• Field-Induced Spin Excitations in the Spin-1/2 Triangular-Lattice Antiferromagnet CsYbSe${}_2$
• Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe${}_2$
• Exchange renormalized crystal field excitation in a quantum Ising magnet KTmSe${}_2$
• Tracking the evolution from isolated dimers to many-body entanglement in NaLu${}_x$Yb${}_{1-x}$Se${}_2$
• Nearly-Resonant Crystalline-Phononic Coupling in Quantum Spin Liquid Candidate CsYbSe${}_2$
• Magnetic properties of a spin-orbit entangled Jeff = 1/2 honeycomb lattice
• Quantifying uncertainties in crystal electric field Hamiltonian fits to neutron data
• Crystalline electric field excitations and their nonlinear splitting under magnetic fields in YbOCl
• Magnetotropic susceptibility
• Field-driven transition from quantum spin liquid to magnetic order in triangular-lattice antiferromagnets
• Heat conduction in magnetic insulators via hybridization of acoustic phonons and spin-flip excitations
• Field-Induced Magnon Decay, Magnon Shadows, and Roton-like Excitations in the Honeycomb Antiferromagnet YbBr${}_3$