Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds

A few 4d and 5d transition metal compounds with various electron fillings were recently found to exhibit magnetic susceptibilities χ and magnetic moments that deviate from the well-established Kotani model. This model has been considered for decades to be the canonical expression for descriing the t...

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Main Authors: Ying Li, Ram Seshadri, Stephen D. Wilson, Anthony K. Cheetham, Roser Valentí
Format: Article
Language:English
Published: American Physical Society 2025-03-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.L012083
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author Ying Li
Ram Seshadri
Stephen D. Wilson
Anthony K. Cheetham
Roser Valentí
author_facet Ying Li
Ram Seshadri
Stephen D. Wilson
Anthony K. Cheetham
Roser Valentí
author_sort Ying Li
collection DOAJ
description A few 4d and 5d transition metal compounds with various electron fillings were recently found to exhibit magnetic susceptibilities χ and magnetic moments that deviate from the well-established Kotani model. This model has been considered for decades to be the canonical expression for descriing the temperature dependence of magnetism in systems with nonnegligible spin-orbit coupling effects. In this paper, we uncover the origin of such discrepancies and determine the applicability and limitations of the Kotani model by calculating the temperature dependence of the magnetic moments of a series of 4d (Ru-based) and 5d (W-based) systems at different electron fillings. For this purpose, we perform exact diagonalization of ab initio-derived relativistic multiorbital Hubbard models on finite clusters and compute their magnetic susceptibilities. Comparison with experimentally measured magnetic properties indicates that contributions such as a temperature-independent χ_{0} background, crystal field effects, Coulomb and Hund's couplings, and intersite interactions—not included in the Kotani model—are especially crucial for correctly describing the temperature dependence of χ and magnetic moments at various electron fillings in these systems. Based on our results, we propose a generalized approach beyond the Kotani model to accurately describe their magnetism.
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spelling doaj-art-d1b5ffbe5e674ab383bb2a57a23ab0852025-08-20T02:10:02ZengAmerican Physical SocietyPhysical Review Research2643-15642025-03-0171L01208310.1103/PhysRevResearch.7.L012083Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compoundsYing LiRam SeshadriStephen D. WilsonAnthony K. CheethamRoser ValentíA few 4d and 5d transition metal compounds with various electron fillings were recently found to exhibit magnetic susceptibilities χ and magnetic moments that deviate from the well-established Kotani model. This model has been considered for decades to be the canonical expression for descriing the temperature dependence of magnetism in systems with nonnegligible spin-orbit coupling effects. In this paper, we uncover the origin of such discrepancies and determine the applicability and limitations of the Kotani model by calculating the temperature dependence of the magnetic moments of a series of 4d (Ru-based) and 5d (W-based) systems at different electron fillings. For this purpose, we perform exact diagonalization of ab initio-derived relativistic multiorbital Hubbard models on finite clusters and compute their magnetic susceptibilities. Comparison with experimentally measured magnetic properties indicates that contributions such as a temperature-independent χ_{0} background, crystal field effects, Coulomb and Hund's couplings, and intersite interactions—not included in the Kotani model—are especially crucial for correctly describing the temperature dependence of χ and magnetic moments at various electron fillings in these systems. Based on our results, we propose a generalized approach beyond the Kotani model to accurately describe their magnetism.http://doi.org/10.1103/PhysRevResearch.7.L012083
spellingShingle Ying Li
Ram Seshadri
Stephen D. Wilson
Anthony K. Cheetham
Roser Valentí
Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds
Physical Review Research
title Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds
title_full Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds
title_fullStr Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds
title_full_unstemmed Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds
title_short Microscopic origin of temperature-dependent magnetism in spin-orbit-coupled transition metal compounds
title_sort microscopic origin of temperature dependent magnetism in spin orbit coupled transition metal compounds
url http://doi.org/10.1103/PhysRevResearch.7.L012083
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AT ramseshadri microscopicoriginoftemperaturedependentmagnetisminspinorbitcoupledtransitionmetalcompounds
AT stephendwilson microscopicoriginoftemperaturedependentmagnetisminspinorbitcoupledtransitionmetalcompounds
AT anthonykcheetham microscopicoriginoftemperaturedependentmagnetisminspinorbitcoupledtransitionmetalcompounds
AT roservalenti microscopicoriginoftemperaturedependentmagnetisminspinorbitcoupledtransitionmetalcompounds