Cobalt-based pyroxenes: A new playground for Kitaev physics

• 成果类型: Article
• 署名作者: Maksimov, Pavel A.; Ushakov, Alexey, V; Gubkin, Andrey F.; Redhammer, Guenther J.; Winter, Stephen M.; Kolesnikov, Alexander I.; Santos, Antonio M. dos; Gai, Zheng; Mcguire, Michael A.; Podlesnyak, Andrey; Streltsov, Sergey, V
• 署名单位: Joint Institute for Nuclear Research - Russia; Russian Academy of Sciences; Institute of Metal Physics UB RAS; Ural Federal University; Salzburg University; Wake Forest University; Wake Forest University; United States Department of Energy (DOE); Oak Ridge National Laboratory; United States Department of Energy (DOE); Oak Ridge National Laboratory; Center for Nanophase Materials Sciences; United States Department of Energy (DOE); Oak Ridge National Laboratory; Ural Federal University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11568
• DOI: 10.1073/pnas.2409154121
• 发表日期: 2024-10-22
• 关键词: spin; Visualization; criticality; state

摘要

Recent advances in the study of cobaltites have unveiled their potential as a promising platform for realizing Kitaev physics in honeycomb systems and the Ising model in weakly coupled chain materials. In this manuscript, we explore the magnetic properties of pyroxene SrCoGe2O6 using a combination of neutron scattering, ab initio methods, and linear spin-wave theory. Through careful examination of inelastic neutron scattering powder spectra, we propose a modified Kitaev model to accurately describe the twisted chains of edge-sharing octahedra surrounding Co2+ ions. The extended Kitaev-Heisenberg model, including a significant anisotropic bond- dependent exchange term with K /| J | = 0.96, is identified as the key descriptor of the magnetic interactions in SrCoGe2O6. Furthermore, our heat capacity measurements reveal an effect of an external magnetic field (approximately 13 T) which shifts the system from a fragile antiferromagnetic ordering with T N = 9 K to a field-induced state. We argue that pyroxenes, particularly those modified by substituting Ge with Si and its less extended p orbitals, emerge as a platform for the Kitaev model. This opens up possibilities for advancing our understanding of Kitaev physics.