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Xie T, Eberharter AA, Xing J, Nishimoto S, Brando M, Khanenko P, Sichelschmidt J, Turrini AA, Mazzone DG, Naumov PG, Sanjeewa LD, Harrison N, Sefat AS, Normand B, Läuchli AM, Podlesnyak A, Nikitin SE. Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe 2. NPJ Quantum Mater 2023; 8:48. [PMID: 38666238 PMCID: PMC11041694 DOI: 10.1038/s41535-023-00580-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/11/2023] [Indexed: 04/28/2024]
Abstract
Fifty years after Anderson's resonating valence-bond proposal, the spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) remains the ultimate platform to explore highly entangled quantum spin states in proximity to magnetic order. Yb-based delafossites are ideal candidate TLHAF materials, which allow experimental access to the full range of applied in-plane magnetic fields. We perform a systematic neutron scattering study of CsYbSe2, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling. We then measure the complex evolution of the excitation spectrum, finding extensive continuum features near the 120°-ordered state, throughout the 1/3-magnetization plateau and beyond this up to saturation. We perform cylinder matrix-product-state (MPS) calculations to obtain an unbiased numerical benchmark for the TLHAF and spectacular agreement with the experimental spectra. The measured and calculated longitudinal spectral functions reflect the role of multi-magnon bound and scattering states. These results provide valuable insight into unconventional field-induced spin excitations in frustrated quantum materials.
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Affiliation(s)
- Tao Xie
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - A. A. Eberharter
- Institut für Theoretische Physik, Universität Innsbruck, Innsbruck, Austria
| | - Jie Xing
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - S. Nishimoto
- Department of Physics, Technical University Dresden, 01069 Dresden, Germany
- Institute for Theoretical Solid State Physics, IFW Dresden, 01069 Dresden, Germany
| | - M. Brando
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - P. Khanenko
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - J. Sichelschmidt
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - A. A. Turrini
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - D. G. Mazzone
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - P. G. Naumov
- Quantum Criticality and Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
- Orange Quantum Systems B.V., Elektronicaweg 2, 2628 XG Delft, The Netherlands
| | - L. D. Sanjeewa
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - N. Harrison
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - Athena S. Sefat
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - B. Normand
- Laboratory for Theoretical and Computational Physics, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A. M. Läuchli
- Laboratory for Theoretical and Computational Physics, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A. Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - S. E. Nikitin
- Quantum Criticality and Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
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Häußler E, Sichelschmidt J, Baenitz M, Doert T. Synthesis and characterization of the solid-solution series NaYb 1−x
Lu
x
S 2 in the α-NaFeO 2 structure type. Acta Cryst Sect A 2022. [DOI: 10.1107/s2053273322092221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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Ehlers D, Kliemt K, Krellner C, Geibel C, Sichelschmidt J. Uniaxial and fourfold basal anisotropy in GdRh 2Si 2. J Phys Condens Matter 2020; 32:495801. [PMID: 32914761 DOI: 10.1088/1361-648x/abb17d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The magnetocrystalline anisotropy of GdRh2Si2 is examined in detail via the electron spin resonance (ESR) of its well-localised Gd3+ moments. Below T N = 107 K, long range magnetic order sets in with ferromagnetic layers in the (aa)-plane stacked antiferromagnetically along the c-axis of the tetragonal structure. Interestingly, the easy-plane anisotropy allows for the observation of antiferromagnetic resonance at X- and Q-band microwave frequencies. In addition to the easy-plane anisotropy we have also quantified the weaker fourfold anisotropy within the easy plane. The obtained resonance fields are modelled in terms of eigenoscillations of the two antiferromagnetically coupled sublattices. Conversely, this model provides plots of the eigenfrequencies as a function of field and the specific anisotropy constants. Such calculations have rarely been done. Therefore our analysis is prototypical for other systems with fourfold in-plane anisotropy. It is demonstrated that the experimental in-plane ESR data may be crucial for a precise knowledge of the out-of-plane anisotropy.
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Affiliation(s)
- D Ehlers
- Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden, Germany. Experimentalphysik V, Zentrum für elektronische Korrelationen und Magnetismus, Universität Augsburg, 86135 Augsburg, Germany
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Sichelschmidt J, Herzog A, Jeevan HS, Geibel C, Steglich F, Iizuka T, Kimura S. Far-infrared optical conductivity of CeCu2Si2. J Phys Condens Matter 2013; 25:065602. [PMID: 23315274 DOI: 10.1088/0953-8984/25/6/065602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We investigated the optical reflectivity of the heavy-fermion metal CeCu(2)Si(2) in the energy range 3 meV-30 eV for temperatures between 4 and 300 K. The results for the charge dynamics indicate a behavior that is expected for the formation of a coherent heavy quasiparticle state: upon cooling the spectra of the optical conductivity indicate a narrowing of the coherent response. Below temperatures of 30 K a considerable suppression of conductivity evolves below a peak structure at 13 meV. We assign this gap-like feature to strong electron correlations due to the 4f-conduction electron hybridization.
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Affiliation(s)
- J Sichelschmidt
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
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5
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Guritanu V, Seiro S, Sichelschmidt J, Caroca-Canales N, Iizuka T, Kimura S, Geibel C, Steglich F. Optical study of archetypical valence-fluctuating Eu systems. Phys Rev Lett 2012; 109:247207. [PMID: 23368375 DOI: 10.1103/physrevlett.109.247207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Indexed: 06/01/2023]
Abstract
We have investigated the optical conductivity of the prominent valence-fluctuating compounds EuIr(2)Si(2) and EuNi(2)P(2) in the infrared energy range to get new insights into the electronic properties of valence-fluctuating systems. For both compounds, we observe upon cooling the formation of a renormalized Drude response, a partial suppression of the optical conductivity below 100 meV, and the appearance of a midinfrared peak at 0.15 eV for EuIr(2)Si(2) and 0.13 eV for EuNi(2)P(2). Most remarkably, our results show a strong similarity with the optical spectra reported for many Ce- or Yb-based heavy-fermion metals and intermediate valence systems, although the phase diagrams and the temperature dependence of the valence differ strongly between Eu systems and Ce- or Yb-based systems. This suggests that the hybridization between 4f and conduction electrons, which is responsible for the properties of Ce and Yb systems, plays an important role in valence-fluctuating Eu systems.
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Affiliation(s)
- V Guritanu
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
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Belov SI, Kutuzov AS, Kochelaev BI, Sichelschmidt J. Kondo lattice with heavy fermions: peculiarities of spin kinetics. J Phys Condens Matter 2012; 24:365601. [PMID: 22906979 DOI: 10.1088/0953-8984/24/36/365601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A model of spin relaxation of Kondo lattices is proposed to explain the angular dependence of the electron spin resonance (ESR) parameters in the heavy fermion compounds Y bIr(2)Si(2) and Y bRh(2)Si(2). A perturbational scaling approach reveals a collective spin motion of Yb ions with conduction electrons in the bottleneck regime. A common energy scale due to the Kondo effect regulates the temperature dependence of different kinetic coefficients to result in a mutual cancelation of all divergent parts in a collective spin mode. The angular dependence of the ESR intensity, linewidth and resonant frequency is shown to be in good agreement with experimental data on Y bIr(2)Si(2) and Y bRh(2)Si(2). In particular, the unexpectedly weak dependence of the ESR intensity on the orientation of the microwave magnetic field agrees with the properties of the discussed model.
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Affiliation(s)
- S I Belov
- Kazan Federal University, Kremlevskaya, 18, Kazan 420008, Russian Federation.
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Förster T, Sichelschmidt J, Krellner C, Geibel C, Steglich F. Electron spin resonance of the ferromagnetic Kondo lattice CeRuPO. J Phys Condens Matter 2010; 22:435603. [PMID: 21403333 DOI: 10.1088/0953-8984/22/43/435603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The spin dynamics of the ferromagnetic Kondo lattice CeRuPO is investigated by electron spin resonance (ESR) at microwave frequencies of 1, 9.4 and 34 GHz. The measured resonance can be ascribed to a rarely observed bulk Ce(3 + ) resonance in a metallic Ce compound and can be followed below the ferromagnetic transition temperature T(C) = 14 K. At T > T(C) the interplay between the RKKY exchange interaction and the crystal electric field anisotropy determines the ESR parameters. Near T(C) the spin-relaxation rate is influenced by the critical fluctuations of the order parameter.
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Affiliation(s)
- T Förster
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
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Gruner T, Wykhoff J, Sichelschmidt J, Krellner C, Geibel C, Steglich F. Anisotropic electron spin resonance of Y bIr₂Si₂. J Phys Condens Matter 2010; 22:135602. [PMID: 21389517 DOI: 10.1088/0953-8984/22/13/135602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A series of electron spin resonance (ESR) experiments were performed on a single crystal of the heavy fermion metal Y bIr₂Si₂ to map out the anisotropy of the ESR-intensity I(ESR) which is governed by the microwave field component of the g-factor. The temperature dependencies of I(ESR)(T) and g(T) were measured for different orientations and compared within the range 2.6 K ≤ T ≤ 16 K. The analysis of the intensity dependence on the crystal orientation with respect to both the direction of the microwave field and the static magnetic field revealed remarkable features: the intensity variation with respect to the direction of the microwave field was found to be one order of magnitude smaller than expected from the g-factor anisotropy. Furthermore, we observed a weak basal plane anisotropy of the ESR parameters which we interpret to be an intrinsic sample property.
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Affiliation(s)
- T Gruner
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
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Schaufuss U, Kataev V, Zvyagin AA, Büchner B, Sichelschmidt J, Wykhoff J, Krellner C, Geibel C, Steglich F. Evolution of the Kondo state of YbRh2Si2 probed by high-field ESR. Phys Rev Lett 2009; 102:076405. [PMID: 19257699 DOI: 10.1103/physrevlett.102.076405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Indexed: 05/27/2023]
Abstract
An electron spin resonance (ESR) study of the heavy fermion compound YbRh2Si2 for fields up to approximately 8 T reveals a strongly anisotropic signal in the Kondo state below approximately 25 K. A similarity between the T dependence of the ESR parameters and that of the specific heat and the 29Si nuclear magnetic resonance data gives evidence that the ESR response is given by heavy fermions. Tuning the Kondo effect on the 4f states with magnetic fields approximately 2-8 T and temperature 2-25 K yields a gradual change of the ESR g factor and linewidth which reflects the evolution of the Kondo state in this Kondo lattice system.
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Affiliation(s)
- U Schaufuss
- IFW Dresden, Institute for Solid State Research, Post Office Box 270116, D-01171 Dresden, Germany
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Krellner C, Förster T, Jeevan H, Geibel C, Sichelschmidt J. Relevance of ferromagnetic correlations for the electron spin resonance in Kondo lattice systems. Phys Rev Lett 2008; 100:066401. [PMID: 18352492 DOI: 10.1103/physrevlett.100.066401] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Indexed: 05/26/2023]
Abstract
Electron spin resonance (ESR) measurements of the ferromagnetic (FM) Kondo lattice system CeRuPO show a well defined ESR signal which is related to the Ce3+ magnetism. In contrast, no ESR could be observed in the antiferromagnetic (AFM) homologue CeOsPO. Additionally, we detect an ESR signal in ferromagnetic YbRh while it was absent in a number of Ce or Yb intermetallic compounds with dominant AFM exchange. Thus, the observation of an ESR signal in a Kondo lattice is neither specific to Yb nor to the proximity to a quantum critical point, but seems to be connected to the presence of FM fluctuations. These conclusions not only provide a basic concept to understand the ESR in Kondo lattice systems even well below the Kondo temperature (as observed in YbRh2Si2) but point out ESR as a prime method to investigate directly the spin dynamics of the Kondo ion.
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Affiliation(s)
- C Krellner
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
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Sichelschmidt J, Voevodin V, Im HJ, Kimura S, Rosner H, Leithe-Jasper A, Schnelle W, Burkhardt U, Mydosh JA, Grin Y, Steglich F. Optical pseudogap from iron states in filled skutterudites AFe4Sb12 (A=Yb, Ca, Ba). Phys Rev Lett 2006; 96:037406. [PMID: 16486770 DOI: 10.1103/physrevlett.96.037406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Indexed: 05/06/2023]
Abstract
Optical investigations are presented of the filled skutterudites AFe4Sb12 with divalent cations A=Yb, Ca, Ba. For each of these compounds a very similar pseudogap structure in the optical conductivity develops in the far-infrared spectral region at temperatures below 90 K. Highly accurate local-density approximation electronic band structure calculations can consistently explain the origin of the pseudogap structure generated largely by transition metal 3d states. In particular, a 4f-conduction electron hybridization or strong correlations can be ruled out as origin for the pseudogap.
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Affiliation(s)
- J Sichelschmidt
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
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12
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Sichelschmidt J, Ivanshin VA, Ferstl J, Geibel C, Steglich F. Low temperature electron spin resonance of the Kondo ion in a heavy fermion metal: YbRh2Si2. Phys Rev Lett 2003; 91:156401. [PMID: 14611480 DOI: 10.1103/physrevlett.91.156401] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Indexed: 05/24/2023]
Abstract
We report an electron spin resonance (ESR) study on single crystals of the heavy fermion metal YbRh2Si2 which shows pronounced non-Fermi liquid behavior related to a close antiferromagnetic quantum critical point. It is shown that the observed ESR spectra can be ascribed to a bulk Yb3+ resonance. This is the first observation of ESR of the Kondo ion itself in a dense Kondo lattice system. The ESR signal occurs below the Kondo temperature (T(K)) which thus indicates the existence of large unscreened Yb3+ moments below T(K). We observe the spin dynamics as well as the static magnetic properties of the Yb3+ spins to be consistent with the results of nuclear magnetic resonance and magnetic susceptibility.
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Affiliation(s)
- J Sichelschmidt
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
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Sichelschmidt J, Elschner B, Loidl A, Kochelaev BI. EPR study of the dynamic spin susceptibility in heavily doped YBa2Cu3O6+ delta. Phys Rev B Condens Matter 1995; 51:9199-9207. [PMID: 9977562 DOI: 10.1103/physrevb.51.9199] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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