1
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Martinelli L, Wohlfeld K, Pelliciari J, Arpaia R, Brookes NB, Di Castro D, Fernandez MG, Kang M, Krockenberger Y, Kummer K, McNally DE, Paris E, Schmitt T, Yamamoto H, Walters A, Zhou KJ, Braicovich L, Comin R, Sala MM, Devereaux TP, Daghofer M, Ghiringhelli G. Collective Nature of Orbital Excitations in Layered Cuprates in the Absence of Apical Oxygens. PHYSICAL REVIEW LETTERS 2024; 132:066004. [PMID: 38394564 DOI: 10.1103/physrevlett.132.066004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 10/27/2023] [Accepted: 12/21/2023] [Indexed: 02/25/2024]
Abstract
We have investigated the 3d orbital excitations in CaCuO_{2} (CCO), Nd_{2}CuO_{4} (NCO), and La_{2}CuO_{4} (LCO) using high-resolution resonant inelastic x-ray scattering. In LCO they behave as well-localized excitations, similarly to several other cuprates. On the contrary, in CCO and NCO the d_{xy} orbital clearly disperses, pointing to a collective character of this excitation (orbiton) in compounds without apical oxygen. We ascribe the origin of the dispersion as stemming from a substantial next-nearest-neighbor (NNN) orbital superexchange. Such an exchange leads to the liberation of the orbiton from its coupling to magnons, which is associated with the orbiton hopping between nearest neighbor copper sites. Finally, we show that the exceptionally large NNN orbital superexchange can be traced back to the absence of apical oxygens suppressing the charge transfer energy.
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Affiliation(s)
- Leonardo Martinelli
- Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Krzysztof Wohlfeld
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warsaw, Poland
| | - Jonathan Pelliciari
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Riccardo Arpaia
- Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Nicholas B Brookes
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Daniele Di Castro
- Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
- CNR-SPIN, Università di Roma Tor Vergata, Via del Politecnico 1, I-00133 Roma, Italy
| | | | - Mingu Kang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | - Kurt Kummer
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Daniel E McNally
- Photon Science Division, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Eugenio Paris
- Photon Science Division, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Thorsten Schmitt
- Photon Science Division, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Hideki Yamamoto
- NTT Basic Research Laboratories, NTT Corporation, Atsugi, Kanagawa, 243-0198, Japan
| | - Andrew Walters
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Ke-Jin Zhou
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Lucio Braicovich
- Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Marco Moretti Sala
- Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Thomas P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC, Menlo Park, California 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Maria Daghofer
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
- Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
| | - Giacomo Ghiringhelli
- Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- CNR-SPIN, Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
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2
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Li XT, Tu SJ, Chaix L, Fawaz C, d'Astuto M, Li X, Yakhou-Harris F, Kummer K, Brookes NB, Garcia-Fernandez M, Zhou KJ, Lin ZF, Yuan J, Jin K, Dean MPM, Liu X. Evolution of the Magnetic Excitations in Electron-Doped La_{2-x}Ce_{x}CuO_{4}. PHYSICAL REVIEW LETTERS 2024; 132:056002. [PMID: 38364146 DOI: 10.1103/physrevlett.132.056002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 12/12/2023] [Indexed: 02/18/2024]
Abstract
We investigated the high energy spin excitations in electron-doped La_{2-x}Ce_{x}CuO_{4}, a cuprate superconductor, by resonant inelastic x-ray scattering (RIXS) measurements. Efforts were paid to disentangle the paramagnon signal from non-spin-flip spectral weight mixing in the RIXS spectrum at Q_{∥}=(0.6π,0) and (0.9π,0) along the (1 0) direction. Our results show that, for doping level x from 0.07 to 0.185, the variation of the paramagnon excitation energy is marginal. We discuss the implication of our results in connection with the evolution of the electron correlation strength in this system.
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Affiliation(s)
- X T Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - S J Tu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - L Chaix
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - C Fawaz
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - M d'Astuto
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - X Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - F Yakhou-Harris
- European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex, France
| | - K Kummer
- European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex, France
| | - N B Brookes
- European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex, France
| | | | - Ke-Jin Zhou
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Z F Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J Yuan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - K Jin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - M P M Dean
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - X Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Center for Transformative Science, ShanghaiTech University, Shanghai 201210, China
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3
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Silkin VM, Drechsler SL, Efremov DV. Unusual Low-Energy Collective Charge Excitations in High- Tc Cuprate Superconductors. J Phys Chem Lett 2023; 14:8060-8068. [PMID: 37655950 PMCID: PMC10510710 DOI: 10.1021/acs.jpclett.3c01871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 08/14/2023] [Indexed: 09/02/2023]
Abstract
Despite decades of intensive experimental and theoretical efforts, the physics of cuprate high-temperature superconductors in general, and, in particular, their normal state, is still under debate. Here, we report our investigation of low-energy charge excitations in the normal state. We find that the peculiarities of the electronic band structure at low energies have a profound impact on the nature of the intraband collective modes. It gives rise to a new kind of mode with huge intensity and non-Lorentzian spectral function in addition to well-known collective excitations like conventional plasmons and spin fluctuation. We predict two such modes with maximal spectral weight in the nodal and antinodal directions. Additionally, we found a long-living quasi-one-dimensional plasmon becoming an intense soft mode over an extended momentum range along the antinodal direction. These modes might explain some of the resonant inelastic X-ray scattering spectroscopy data.
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Affiliation(s)
- Vyacheslav M. Silkin
- Donostia
International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain
- Departamento
de Polímeros y Materiales Avanzados: Física,
Química y Tecnología, Facultad de Ciencias
Químicas, Universidad del País
Vasco UPV/EHU, 20080 San Sebastián/Donostia, Basque Country, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Stefan-Ludwig Drechsler
- Leibniz
Institute for Solid State and Materials Research IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Dmitry V. Efremov
- Leibniz
Institute for Solid State and Materials Research IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
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4
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Poelchen G, Hellwig J, Peters M, Usachov DY, Kliemt K, Laubschat C, Echenique PM, Chulkov EV, Krellner C, Parkin SSP, Vyalikh DV, Ernst A, Kummer K. Long-lived spin waves in a metallic antiferromagnet. Nat Commun 2023; 14:5422. [PMID: 37669952 PMCID: PMC10480465 DOI: 10.1038/s41467-023-40963-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 08/17/2023] [Indexed: 09/07/2023] Open
Abstract
Collective spin excitations in magnetically ordered crystals, called magnons or spin waves, can serve as carriers in novel spintronic devices with ultralow energy consumption. The generation of well-detectable spin flows requires long lifetimes of high-frequency magnons. In general, the lifetime of spin waves in a metal is substantially reduced due to a strong coupling of magnons to the Stoner continuum. This makes metals unattractive for use as components for magnonic devices. Here, we present the metallic antiferromagnet CeCo2P2, which exhibits long-living magnons even in the terahertz (THz) regime. For CeCo2P2, our first-principle calculations predict a suppression of low-energy spin-flip Stoner excitations, which is verified by resonant inelastic X-ray scattering measurements. By comparison to the isostructural compound LaCo2P2, we show how small structural changes can dramatically alter the electronic structure around the Fermi level leading to the classical picture of the strongly damped magnons intrinsic to metallic systems. Our results not only demonstrate that long-lived magnons in the THz regime can exist in bulk metallic systems, but they also open a path for an efficient search for metallic magnetic systems in which undamped THz magnons can be excited.
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Affiliation(s)
- G Poelchen
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble, France.
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062, Dresden, Germany.
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany.
| | - J Hellwig
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - M Peters
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - D Yu Usachov
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
| | - K Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - C Laubschat
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062, Dresden, Germany
| | - P M Echenique
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - E V Chulkov
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018, Donostia-San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080, Donostia-San Sebastián, Spain
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - S S P Parkin
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
- Institut für Theoretische Physik, Johannes Kepler Universität, 4040, Linz, Austria
| | - K Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble, France.
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5
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Mai P, Nichols NS, Karakuzu S, Bao F, Del Maestro A, Maier TA, Johnston S. Robust charge-density-wave correlations in the electron-doped single-band Hubbard model. Nat Commun 2023; 14:2889. [PMID: 37210389 DOI: 10.1038/s41467-023-38566-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 05/04/2023] [Indexed: 05/22/2023] Open
Abstract
There is growing evidence that the hole-doped single-band Hubbard and t - J models do not have a superconducting ground state reflective of the high-temperature cuprate superconductors but instead have striped spin- and charge-ordered ground states. Nevertheless, it is proposed that these models may still provide an effective low-energy model for electron-doped materials. Here we study the finite temperature spin and charge correlations in the electron-doped Hubbard model using quantum Monte Carlo dynamical cluster approximation calculations and contrast their behavior with those found on the hole-doped side of the phase diagram. We find evidence for a charge modulation with both checkerboard and unidirectional components decoupled from any spin-density modulations. These correlations are inconsistent with a weak-coupling description based on Fermi surface nesting, and their doping dependence agrees qualitatively with resonant inelastic x-ray scattering measurements. Our results provide evidence that the single-band Hubbard model describes the electron-doped cuprates.
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Affiliation(s)
- Peizhi Mai
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6494, USA
- Department of Physics and Institute of Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Nathan S Nichols
- Data Science and Learning Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Seher Karakuzu
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6494, USA
- Center for Computational Quantum Physics, Flatiron Institute, 162 5th Avenue, New York, NY, 10010, USA
| | - Feng Bao
- Department of Mathematics, Florida State University, Tallahassee, FL, 32306, USA
| | - Adrian Del Maestro
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA
- Institute of Advanced Materials and Manufacturing, The University of Tennessee, Knoxville, TN, 37996, USA
- Min H. Kao Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Thomas A Maier
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6494, USA
| | - Steven Johnston
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA.
- Institute of Advanced Materials and Manufacturing, The University of Tennessee, Knoxville, TN, 37996, USA.
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6
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Wang L, He G, Yang Z, Garcia-Fernandez M, Nag A, Zhou K, Minola M, Tacon ML, Keimer B, Peng Y, Li Y. Paramagnons and high-temperature superconductivity in a model family of cuprates. Nat Commun 2022; 13:3163. [PMID: 35672416 PMCID: PMC9174205 DOI: 10.1038/s41467-022-30918-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Cuprate superconductors have the highest critical temperatures (Tc) at ambient pressure, yet a consensus on the superconducting mechanism remains to be established. Finding an empirical parameter that limits the highest reachable Tc can provide crucial insight into this outstanding problem. Here, in the first two Ruddlesden-Popper members of the model Hg-family of cuprates, which are chemically nearly identical and have the highest Tc among all cuprate families, we use inelastic photon scattering to reveal that the energy of magnetic fluctuations may play such a role. In particular, we observe the single-paramagnon spectra to be nearly identical between the two compounds, apart from an energy scale difference of ~30% which matches their difference in Tc. The empirical correlation between paramagnon energy and maximal Tc is further found to extend to other cuprate families with relatively high Tc’s, hinting at a fundamental connection between them. Finding a parameter that limits the critical temperature of cuprate superconductors can provide crucial insight on the superconducting mechanism. Here, the authors use inelastic photon scattering on two Ruddlesden-Popper members of the model Hg-family of cuprates to reveal that the energy of magnetic fluctuations may play such a role, and suggest that the Cooper pairing is mediated by paramagnons.
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7
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Orgiani P, Galdi A, Schlom DG, Maritato L. Normal-State Transport Properties of Infinite-Layer Sr 1-xLa xCuO 2 Electron-Doped Cuprates in Optimal- and Over-Doped Regimes. NANOMATERIALS 2022; 12:nano12101709. [PMID: 35630928 PMCID: PMC9146696 DOI: 10.3390/nano12101709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/08/2022] [Accepted: 05/13/2022] [Indexed: 12/03/2022]
Abstract
Transport properties of electron-doped cuprate Sr1−xLaxCuO2 thin films have been investigated as a function of doping. In particular, optimal- and over-doped samples were obtained by tuning the Sr:La stoichiometric ratio. Optimal-doped samples show a non-Fermi liquid behavior characterized by linear dependence of the resistivity from room temperature down to intermediate temperature (about 150–170 K). However, by approaching temperatures in the superconducting transition, a Fermi-liquid behavior-characterized by a T2-scaling law-was observed. Once established, the transition from a linear-T to a quadratic-T2 behavior was successfully traced back in over-doped samples, even occurring at lower temperatures. In addition, the over-doped samples show a crossover to a linear-T to a logarithmic dependence at high temperatures compatible with anti-ferromagnetic spin fluctuations dominating the normal state properties of electron-doped cuprates.
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Affiliation(s)
- Pasquale Orgiani
- CNR-IOM, TASC Laboratory in Area Science Park, 34139 Trieste, Italy
- Correspondence:
| | - Alice Galdi
- Dipartimento di Ingegneria Industriale, Università degli Studi di Salerno, 84084 Fisciano, Italy; (A.G.); (L.M.)
| | - Darrell G. Schlom
- Department of Material Science and Engineering, Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA;
| | - Luigi Maritato
- Dipartimento di Ingegneria Industriale, Università degli Studi di Salerno, 84084 Fisciano, Italy; (A.G.); (L.M.)
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8
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Schmehr JL, Mion TR, Porter Z, Aling M, Cao H, Upton MH, Islam Z, He RH, Sensarma R, Trivedi N, Wilson SD. Overdamped Antiferromagnetic Strange Metal State in Sr_{3}IrRuO_{7}. PHYSICAL REVIEW LETTERS 2019; 122:157201. [PMID: 31050510 DOI: 10.1103/physrevlett.122.157201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/24/2019] [Indexed: 06/09/2023]
Abstract
The unconventional electronic ground state of Sr_{3}IrRuO_{7} is explored via resonant x-ray scattering techniques and angle-resolved photoemission measurements. As the Ru content approaches x=0.5 in Sr_{3}(Ir_{1-x}Ru_{x})_{2}O_{7}, intermediate to the J_{eff}=1/2 Mott state in Sr_{3}Ir_{2}O_{7} and the quantum critical metal in Sr_{3}Ru_{2}O_{7}, a thermodynamically distinct metallic state emerges. The electronic structure of this intermediate phase lacks coherent quasiparticles, and charge transport exhibits a linear temperature dependence over a wide range of temperatures. Spin dynamics associated with the long-range antiferromagnetism of this phase show nearly local, overdamped magnetic excitations and an anomalously large energy scale of 200 meV-an energy far in excess of exchange energies present within either the Sr_{3}Ir_{2}O_{7} or Sr_{3}Ru_{2}O_{7} solid-solution end points. Overdamped quasiparticle dynamics driven by strong spin-charge coupling are proposed to explain the incoherent spectral features of the strange metal state in Sr_{3}IrRuO_{7}.
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Affiliation(s)
- Julian L Schmehr
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Thomas R Mion
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Zach Porter
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Michael Aling
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Huibo Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Mary H Upton
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Zahirul Islam
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Rui-Hua He
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Rajdeep Sensarma
- Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Nandini Trivedi
- Mathematics Department, The Ohio State University, Columbus, Ohio 43210, USA
| | - Stephen D Wilson
- Materials Department, University of California, Santa Barbara, California 93106, USA
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9
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Hepting M, Chaix L, Huang EW, Fumagalli R, Peng YY, Moritz B, Kummer K, Brookes NB, Lee WC, Hashimoto M, Sarkar T, He JF, Rotundu CR, Lee YS, Greene RL, Braicovich L, Ghiringhelli G, Shen ZX, Devereaux TP, Lee WS. Three-dimensional collective charge excitations in electron-doped copper oxide superconductors. Nature 2018; 563:374-378. [PMID: 30429543 DOI: 10.1038/s41586-018-0648-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/22/2018] [Indexed: 11/09/2022]
Abstract
High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides5-7 reveals their charge origin, that is, without mixing with magnetic components5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems8-12 and argued to play a substantial part in mediating high-temperature superconductivity10-12.
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Affiliation(s)
- M Hepting
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - L Chaix
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.,Université Grenoble Alpes, CNRS, Institut Néel, Grenoble, France
| | - E W Huang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.,Department of Physics, Stanford University, Stanford, CA, USA
| | - R Fumagalli
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
| | - Y Y Peng
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy.,Department of Physics and Seitz Materials Research Lab, University of Illinois, Urbana, IL, USA
| | - B Moritz
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - K Kummer
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - N B Brookes
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - W C Lee
- Department of Physics, Binghamton University, Binghamton, NY, USA
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - T Sarkar
- Department of Physics, Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD, USA
| | - J-F He
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.,Department of Physics, University of Science and Technology of China, Hefei, China
| | - C R Rotundu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - Y S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA
| | - R L Greene
- Department of Physics, Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD, USA
| | - L Braicovich
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy.,European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - G Ghiringhelli
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy.,CNR-SPIN, Politecnico di Milano, Milan, Italy
| | - Z X Shen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
| | - W S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
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10
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Miyamoto T, Matsui Y, Terashige T, Morimoto T, Sono N, Yada H, Ishihara S, Watanabe Y, Adachi S, Ito T, Oka K, Sawa A, Okamoto H. Probing ultrafast spin-relaxation and precession dynamics in a cuprate Mott insulator with seven-femtosecond optical pulses. Nat Commun 2018; 9:3948. [PMID: 30258055 PMCID: PMC6158258 DOI: 10.1038/s41467-018-06312-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 08/23/2018] [Indexed: 11/18/2022] Open
Abstract
A charge excitation in a two-dimensional Mott insulator is strongly coupled with the surrounding spins, which is observed as magnetic-polaron formations of doped carriers and a magnon sideband in the Mott-gap transition spectrum. However, the dynamics related to the spin sector are difficult to measure. Here, we show that pump-probe reflection spectroscopy with seven-femtosecond laser pulses can detect the optically induced spin dynamics in Nd2CuO4, a typical cuprate Mott insulator. The bleaching signal at the Mott-gap transition is enhanced at ~18 fs. This time constant is attributable to the spin-relaxation time during magnetic-polaron formation, which is characterized by the exchange interaction. More importantly, ultrafast coherent oscillations appear in the time evolution of the reflectivity changes, and their frequencies (1400-2700 cm-1) are equal to the probe energy measured from the Mott-gap transition peak. These oscillations can be interpreted as the interference between charge excitations with two magnons originating from charge-spin coupling.
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Affiliation(s)
- T Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Y Matsui
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - T Terashige
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Chiba, 277-8568, Japan
| | - T Morimoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - N Sono
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - H Yada
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - S Ishihara
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan
| | - Y Watanabe
- Department of Chemistry, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - S Adachi
- Department of Chemistry, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - T Ito
- National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8565, Ibaraki, Japan
| | - K Oka
- National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8565, Ibaraki, Japan
| | - A Sawa
- National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8565, Ibaraki, Japan
| | - H Okamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan.
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Chiba, 277-8568, Japan.
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11
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Wang Y, Huang EW, Moritz B, Devereaux TP. Magnon Splitting Induced by Charge Transfer in the Three-Orbital Hubbard Model. PHYSICAL REVIEW LETTERS 2018; 120:246401. [PMID: 29956982 DOI: 10.1103/physrevlett.120.246401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Indexed: 06/08/2023]
Abstract
Understanding spin excitations and their connection to unconventional superconductivity have remained central issues since the discovery of cuprates. Direct measurement of the dynamical spin structure factor in the parent compounds can provide key information on important interactions relevant in the doped regime, and variations in the magnon dispersion have been linked closely to differences in crystal structure between families of cuprate compounds. Here, we elucidate the relationship between spin excitations and various controlling factors thought to be significant in high-T_{c} materials by systematically evaluating the dynamical spin structure factor for the three-orbital Hubbard model, revealing differences in the spin dispersion along the Brillouin zone axis and the diagonal. Generally, we find that the absolute energy scale and momentum dependence of the excitations primarily are sensitive to the effective charge-transfer energy, while changes in the on-site Coulomb interactions have little effect on the details of the dispersion. In particular, our result highlights the splitting between spin excitations along the axial and diagonal directions in the Brillouin zone. This splitting decreases with increasing charge-transfer energy and correlates with changes in the apical oxygen position, and general structural variations, for different cuprate families.
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Affiliation(s)
- Yao Wang
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Edwin W Huang
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Brian Moritz
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202, USA
| | - Thomas P Devereaux
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
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12
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Moretti Sala M, Martel K, Henriquet C, Al Zein A, Simonelli L, Sahle CJ, Gonzalez H, Lagier MC, Ponchut C, Huotari S, Verbeni R, Krisch M, Monaco G. A high-energy-resolution resonant inelastic X-ray scattering spectrometer at ID20 of the European Synchrotron Radiation Facility. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:580-591. [PMID: 29488940 DOI: 10.1107/s1600577518001200] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 01/19/2018] [Indexed: 06/08/2023]
Abstract
An end-station for resonant inelastic X-ray scattering and (resonant) X-ray emission spectroscopy at beamline ID20 of ESRF - The European Synchrotron is presented. The spectrometer hosts five crystal analysers in Rowland geometry for large solid angle collection and is mounted on a rotatable arm for scattering in both the horizontal and vertical planes. The spectrometer is optimized for high-energy-resolution applications, including partial fluorescence yield or high-energy-resolution fluorescence detected X-ray absorption spectroscopy and the study of elementary electronic excitations in solids. In addition, it can be used for non-resonant inelastic X-ray scattering measurements of valence electron excitations.
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Affiliation(s)
- M Moretti Sala
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - K Martel
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - C Henriquet
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - A Al Zein
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - L Simonelli
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - Ch J Sahle
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - H Gonzalez
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - M C Lagier
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - C Ponchut
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - S Huotari
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - R Verbeni
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - M Krisch
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - G Monaco
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
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13
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Lu Y, Haverkort MW. Nonperturbative Series Expansion of Green's Functions: The Anatomy of Resonant Inelastic X-Ray Scattering in the Doped Hubbard Model. PHYSICAL REVIEW LETTERS 2017; 119:256401. [PMID: 29303347 DOI: 10.1103/physrevlett.119.256401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Indexed: 06/07/2023]
Abstract
We present a nonperturbative, divergence-free series expansion of Green's functions using effective operators. The method is especially suited for computing correlators of complex operators as a series of correlation functions of simpler forms. We apply the method to study low-energy excitations in resonant inelastic x-ray scattering (RIXS) in doped one- and two-dimensional single-band Hubbard models. The RIXS operator is expanded into polynomials of spin, density, and current operators weighted by fundamental x-ray spectral functions. These operators couple to different polarization channels resulting in simple selection rules. The incident photon energy dependent coefficients help to pinpoint main RIXS contributions from different degrees of freedom. We show in particular that, with parameters pertaining to cuprate superconductors, local spin excitation dominates the RIXS spectral weight over a wide doping range in the cross-polarization channel.
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Affiliation(s)
- Yi Lu
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
- Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany
| | - Maurits W Haverkort
- Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany
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14
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Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex II: Neutron Scattering Instruments. QUANTUM BEAM SCIENCE 2017. [DOI: 10.3390/qubs1030009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Dantz M, Pelliciari J, Samal D, Bisogni V, Huang Y, Olalde-Velasco P, Strocov VN, Koster G, Schmitt T. Quenched Magnon excitations by oxygen sublattice reconstruction in (SrCuO2)n/(SrTiO3)2 superlattices. Sci Rep 2016; 6:32896. [PMID: 27616448 PMCID: PMC5018731 DOI: 10.1038/srep32896] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 08/16/2016] [Indexed: 11/14/2022] Open
Abstract
The recently discovered structural reconstruction in the cuprate superlattice (SrCuO2)n/(SrTiO3)2 has been investigated across the critical value of n = 5 using resonant inelastic x-ray scattering (RIXS). We find that at the critical value of n, the cuprate layer remains largely in the bulk-like two-dimensional structure with a minority of Cu plaquettes being reconstructed. The partial reconstruction leads to quenching of the magnons starting at the Γ-point due to the minority plaquettes acting as scattering points. Although comparable in relative abundance, the doped charge impurities in electron-doped cuprate superconductors do not show this quenching of magnetic excitations.
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Affiliation(s)
- M. Dantz
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J. Pelliciari
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D. Samal
- MESA+ Institute for Nanotechnology, University of Twente, Post Office Box 217, 7500AE Enschede, The Netherlands
| | - V. Bisogni
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Y. Huang
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P. Olalde-Velasco
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V. N. Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - G. Koster
- MESA+ Institute for Nanotechnology, University of Twente, Post Office Box 217, 7500AE Enschede, The Netherlands
| | - T. Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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16
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Gretarsson H, Sung NH, Porras J, Bertinshaw J, Dietl C, Bruin JAN, Bangura AF, Kim YK, Dinnebier R, Kim J, Al-Zein A, Moretti Sala M, Krisch M, Le Tacon M, Keimer B, Kim BJ. Persistent Paramagnons Deep in the Metallic Phase of Sr_{2-x}La_{x}IrO_{4}. PHYSICAL REVIEW LETTERS 2016; 117:107001. [PMID: 27636488 DOI: 10.1103/physrevlett.117.107001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Indexed: 06/06/2023]
Abstract
We have studied the magnetic excitations of electron-doped Sr_{2-x}La_{x}IrO_{4} (0≤x≤0.10) using resonant inelastic x-ray scattering at the Ir L_{3} edge. The long-range magnetic order is rapidly lost with increasing x, but two-dimensional short-range order (SRO) and dispersive magnon excitations with nearly undiminished spectral weight persist well into the metallic part of the phase diagram. The magnons in the SRO phase are heavily damped and exhibit anisotropic softening. Their dispersions are well described by a pseudospin-1/2 Heisenberg model with exchange interactions whose spatial range increases with doping. We also find a doping-independent high-energy magnetic continuum, which is not described by this model. The spin-orbit excitons arising from the pseudospin-3/2 manifold of the Ir ions broaden substantially in the SRO phase, but remain largely separated from the low-energy magnons. Pseudospin-1/2 models are therefore a good starting point for the theoretical description of the low-energy magnetic dynamics of doped iridates.
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Affiliation(s)
- H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - N H Sung
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - J Porras
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - C Dietl
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - Jan A N Bruin
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - A F Bangura
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - Y K Kim
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 151-742, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, South Korea
| | - R Dinnebier
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Al-Zein
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - M Moretti Sala
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - M Krisch
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - M Le Tacon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
- Karlsruher Institut für Technologie, Institut für Festkörperphysik, Hermann-v.-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - B J Kim
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
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17
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da Silva Neto EH, Comin R, He F, Sutarto R, Jiang Y, Greene RL, Sawatzky GA, Damascelli A. Charge ordering in the electron-doped superconductor Nd
2–
x
Ce
x
CuO
4. Science 2015; 347:282-5. [DOI: 10.1126/science.1256441] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Eduardo H. da Silva Neto
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany
- Quantum Materials Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Riccardo Comin
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Feizhou He
- Canadian Light Source, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Ronny Sutarto
- Canadian Light Source, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Yeping Jiang
- Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Richard L. Greene
- Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - George A. Sawatzky
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Andrea Damascelli
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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18
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Piazza BD, Mourigal M, Christensen NB, Nilsen GJ, Tregenna-Piggott P, Perring TG, Enderle M, McMorrow DF, Ivanov DA, Rønnow HM. Fractional excitations in the square lattice quantum antiferromagnet. NATURE PHYSICS 2015; 11:62-68. [PMID: 25729400 PMCID: PMC4340518 DOI: 10.1038/nphys3172] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 10/29/2014] [Indexed: 05/30/2023]
Abstract
Quantum magnets have occupied the fertile ground between many-body theory and low-temperature experiments on real materials since the early days of quantum mechanics. However, our understanding of even deceptively simple systems of interacting spins-1/2 is far from complete. The quantum square-lattice Heisenberg antiferromagnet (QSLHAF), for example, exhibits a striking anomaly of hitherto unknown origin in its magnetic excitation spectrum. This quantum effect manifests itself for excitations propagating with the specific wave vector (π, 0). We use polarized neutron spectroscopy to fully characterize the magnetic fluctuations in the metal-organic compound CFTD, a known realization of the QSLHAF model. Our experiments reveal an isotropic excitation continuum at the anomaly, which we analyse theoretically using Gutzwiller-projected trial wavefunctions. The excitation continuum is accounted for by the existence of spatially-extended pairs of fractional S=1/2 quasiparticles, 2D analogues of 1D spinons. Away from the anomalous wave vector, these fractional excitations are bound and form conventional magnons. Our results establish the existence of fractional quasiparticles in the high-energy spectrum of a quasi-two-dimensional antiferromagnet, even in the absence of frustration.
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Affiliation(s)
- B Dalla Piazza
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland
| | - M Mourigal
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland ; Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9, France ; Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - N B Christensen
- Department of Physics, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby, Denmark ; Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - G J Nilsen
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland ; Department of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ, United Kingdom
| | - P Tregenna-Piggott
- Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - T G Perring
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, United Kingdom
| | - M Enderle
- Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9, France
| | - D F McMorrow
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH, United Kingdom
| | - D A Ivanov
- Institute for Theoretical Physics, ETH Zürich, CH-8093 Zürich, Switzerland ; Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
| | - H M Rønnow
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland ; RIKEN Centre for Emergent Matter Science (CEMS), Wako 351-0198, Japan
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19
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Schmitt T, de Groot FMF, Rubensson JE. Prospects of high-resolution resonant X-ray inelastic scattering studies on solid materials, liquids and gases at diffraction-limited storage rings. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:1065-76. [PMID: 25177995 PMCID: PMC4151682 DOI: 10.1107/s1600577514017123] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/24/2014] [Indexed: 05/29/2023]
Abstract
The spectroscopic technique of resonant inelastic X-ray scattering (RIXS) will particularly profit from immensely improved brilliance of diffraction-limited storage rings (DLSRs). In RIXS one measures the intensities of excitations as a function of energy and momentum transfer. DLSRs will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size to new limits. With RIXS one nowadays probes a broad range of electronic systems reaching from simple molecules to complex materials displaying phenomena like peculiar magnetism, two-dimensional electron gases, superconductivity, photovoltaic energy conversion and heterogeneous catalysis. In this article the types of improved RIXS studies that will become possible with X-ray beams from DLSRs are envisioned.
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Affiliation(s)
- Thorsten Schmitt
- Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, Swiss Light Source, WSLA/123, 5232 Villigen PSI, Switzerland
| | - Frank M. F. de Groot
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, The Netherlands
| | - Jan-Erik Rubensson
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala 751 20, Sweden
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