How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator

article How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator published yes Dorota Gotfryd author Ekaterina Paerschke author 8275014E-6063-11E9-9B7F-6338E66974250000-0003-0853-8182 Jiri Chaloupka author Andrzej M. Oles author Krzysztof Wohlfeld author MiLe department ISTplus - Postdoctoral Fellowships project The concept of the entanglement between spin and orbital degrees of freedom plays a crucial role in our understanding of various phases and exotic ground states in a broad class of materials, including orbitally ordered materials and spin liquids. We investigate how the spin-orbital entanglement in a Mott insulator depends on the value of the spin-orbit coupling of the relativistic origin. To this end, we numerically diagonalize a one-dimensional spin-orbital model with Kugel-Khomskii exchange interactions between spins and orbitals on different sites supplemented by the on-site spin-orbit coupling. In the regime of small spin-orbit coupling with regard to the spin-orbital exchange, the ground state to a large extent resembles the one obtained in the limit of vanishing spin-orbit coupling. On the other hand, for large spin-orbit coupling the ground state can, depending on the model parameters, either still show negligible spin-orbital entanglement or evolve to a highly spin-orbitally-entangled phase with completely distinct properties that are described by an effective XXZ model. The presented results suggest that (i) the spin-orbital entanglement may be induced by large on-site spin-orbit coupling, as found in the 5d transition metal oxides, such as the iridates; (ii) for Mott insulators with weak spin-orbit coupling of Ising type, such as, e.g., the alkali hyperoxides, the effects of the spin-orbit coupling on the ground state can, in the first order of perturbation theory, be neglected. https://research-explorer.ista.ac.at/download/7594/7610/2020_PhysRevResearch_Gotfryd.pdf application/pdfno American Physical Society2020 eng Physical Review Research10.1103/PhysRevResearch.2.013353 21 D. Gotfryd, E. Paerschke, J. Chaloupka, A.M. Oles, K. Wohlfeld, Physical Review Research 2 (2020). Gotfryd, D., Paerschke, E., Chaloupka, J., Oles, A. M., & Wohlfeld, K. (2020). How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator. Physical Review Research. American Physical Society. <a href="https://doi.org/10.1103/PhysRevResearch.2.013353">https://doi.org/10.1103/PhysRevResearch.2.013353</a> Gotfryd D, Paerschke E, Chaloupka J, Oles AM, Wohlfeld K. How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator. Physical Review Research. 2020;2(1). doi:<a href="https://doi.org/10.1103/PhysRevResearch.2.013353">10.1103/PhysRevResearch.2.013353</a> Gotfryd, Dorota, et al. “How Spin-Orbital Entanglement Depends on the Spin-Orbit Coupling in a Mott Insulator.” Physical Review Research, vol. 2, no. 1, 013353, American Physical Society, 2020, doi:<a href="https://doi.org/10.1103/PhysRevResearch.2.013353">10.1103/PhysRevResearch.2.013353</a>. Gotfryd D, Paerschke E, Chaloupka J, Oles AM, Wohlfeld K. 2020. How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator. Physical Review Research. 2(1), 013353. D. Gotfryd, E. Paerschke, J. Chaloupka, A. M. Oles, and K. Wohlfeld, “How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator,” Physical Review Research, vol. 2, no. 1. American Physical Society, 2020. Gotfryd, Dorota, Ekaterina Paerschke, Jiri Chaloupka, Andrzej M. Oles, and Krzysztof Wohlfeld. “How Spin-Orbital Entanglement Depends on the Spin-Orbit Coupling in a Mott Insulator.” Physical Review Research. American Physical Society, 2020. <a href="https://doi.org/10.1103/PhysRevResearch.2.013353">https://doi.org/10.1103/PhysRevResearch.2.013353</a>. 75942020-03-20T15:21:10Z2024-10-21T06:02:21Z