Single-ion properties of the transverse-field Ising model material CoNb${}_2$O${}_6$

Abstract

CoNb${}_2$O${}_6$ is one of the few materials that is known to approximate the one-dimensional transverse-field Ising model (1D-TFIM) near its quantum critical point. It has been inferred that Co${}^{2+}$ acts as a pseudo-spin 1/2 with anisotropic exchange interactions that are largely Ising-like, enabling the realization of the TFIM. However, the behavior of CoNb${}_2$O${}_6$ is known to diverge from the ideal TFIM under transverse magnetic fields that are far from the quantum critical point, requiring the consideration of additional anisotropic, bond-dependent (Kitaev-like) terms in the microscopic pseudo-spin 1/2 Hamiltonian. These terms are expected to be controlled in part by single-ion physics, namely the wavefunction for the pseudo-spin 1/2 angular momentum doublet. Here, we present the results of both inelastic neutron scattering measurements and electron paramagnetic resonance spectroscopy on CoNb${}_2$O${}_6$, which elucidate the single-ion physics of Co${}^{2+}$ in CoNb${}_2$O${}_6$ for the first time. We find that the system is well-described by an intermediate spin-orbit coupled Hamiltonian, and the ground state is a well-isolated Kramers doublet with an anisotropic $g$-tensor. We provide the approximate wavefunctions for this doublet, which we expect will be useful in theoretical investigations of the anisotropic exchange interactions.

9 pages, 6 figures

References in corpus (6)

• Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\mu SR$ Experiments
• Weak-field induced nonmagnetic state in a Co-based honeycomb
• Duality and domain wall dynamics in a twisted Kitaev chain
• "Quasi-particle breakdown" in the quasi-one-dimensional Ising ferromagnet CoNb${}_2$O${}_6$
• Kibble-Zurek mechanism in a Dissipative Transverse Ising Chain
• Low Temperature Domain Wall Freezing and Non-Equilibrium Dynamics in the Transverse-Field Ising Model Material CoNb${}_2$O${}_6$

Cited by in corpus (5)

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• Tuning the confinement potential between spinons in the Ising chain CoNb2O6 using longitudinal fields and quantitative determination of the microscopic Hamiltonian
• Spin dynamics of the generalized quantum spin compass chain
• Transforming from Kitaev to Disguised Ising Chain: Application to CoNb${}_2$O${}_6$
• Cobalt-Based Pyroxenes: A New Playground for Kitaev Physics and Ising Model Realization