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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Roy AP, Ss J, Dwij V, Khandelwal A, Chattopadhyay MK, Sathe V, Mittal R, Sastry PU, Achary SN, Tyagi AK, Babu PD, Le MD, Bansal D. Evidence of Strong Orbital-Selective Spin-Orbital-Phonon Coupling in CrVO_{4}. PHYSICAL REVIEW LETTERS 2024; 132:026701. [PMID: 38277598 DOI: 10.1103/physrevlett.132.026701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/05/2023] [Accepted: 12/14/2023] [Indexed: 01/28/2024]
Abstract
Coupling of orbital degree of freedom with a spin exchange, i.e., Kugel-Khomskii-type interaction (KK), governs a host of material properties, including colossal magnetoresistance, enhanced magnetoelectric response, and photoinduced high-temperature magnetism. In general, KK-type interactions lead to deviation in experimental observables of coupled Hamiltonian near or below the magnetic transition. Using diffraction and spectroscopy experiments, here we report anomalous changes in lattice parameters, electronic states, spin dynamics, and phonons at four times the Néel transition temperature (T_{N}) in CrVO_{4}. The temperature is significantly higher than other d-orbital compounds such as manganites and vanadates, where effects are limited to near or below T_{N}. The experimental observations are rationalized using first-principles and Green's function-based phonon and spin simulations that show unprecedentedly strong KK-type interactions via a superexchange process and an orbital-selective spin-phonon coupling coefficient at least double the magnitude previously reported for strongly coupled spin-phonon systems. Our results present an opportunity to explore the effect of KK-type interactions and spin-phonon coupling well above T_{N} and possibly bring various properties closer to application, for example, strong room-temperature magnetoelectric coupling.
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Affiliation(s)
- Aditya Prasad Roy
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Jayakrishnan Ss
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Vivek Dwij
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, Maharashtra 400076, India
| | - Ashish Khandelwal
- Free Electron Laser Utilization Laboratory, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013, India
| | - M K Chattopadhyay
- Free Electron Laser Utilization Laboratory, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Vasant Sathe
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore, Madhya Pradesh 452001, India
| | - Ranjan Mittal
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400085, India
| | - P U Sastry
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400085, India
| | - Srungarpu N Achary
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
- Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Avesh K Tyagi
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
- Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Peram D Babu
- UGC-DAE Consortium for Scientific Research, Mumbai Centre, R5-Shed, BARC, Trombay, Mumbai, Maharashtra 400085, India
| | - Manh Duc Le
- ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX Oxfordshire, United Kingdom
| | - Dipanshu Bansal
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
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3
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Fumega AO, Wong D, Schulz C, Rodríguez F, Blanco-Canosa S. Spectroscopy of the frustrated quantum antiferromagnet Cs 2CuCl 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:495603. [PMID: 34517361 DOI: 10.1088/1361-648x/ac2648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
We investigate the electronic structure of Cs2CuCl4, a material discussed in the framework of a frustrated quantum antiferromagnet, by means of resonant inelastic x-ray scattering (RIXS) and density functional theory (DFT). From the non-dispersive highly localizedddexcitations, we resolve the crystal field splitting of the Cu2+ions in a strongly distorted tetrahedral coordination. This allows us to model the RIXS spectrum within the crystal field theory (CFT), assign theddorbital excitations and retrieve experimentally the values of the crystal field splitting parametersDq,DsandDτ. The electronic structure obtainedab-initioagrees with the RIXS spectrum and modelled by CFT, highlighting the potential of combined spectroscopic, cluster and DFT calculations to determine the electronic ground state of complex materials.
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Affiliation(s)
- Adolfo O Fumega
- Departamento de Física Aplicada, Universidade de Santiago de Compostela, E-15782 Campus Sur s/n, Santiago de Compostela, Spain
- Instituto de Investigacións Tecnolóxicas, Universidade de Santiago de Compostela, E-15782 Campus Sur s/n, Santiago de Compostela, Spain
| | - D Wong
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - C Schulz
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - F Rodríguez
- MALTA TEAM, DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander, Spain
| | - S Blanco-Canosa
- Donostia International Physics Center (DIPC), San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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4
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Voufack AB, Kibalin I, Yan Z, Claiser N, Gueddida S, Gillon B, Porcher F, Gukasov A, Sugimoto K, Lecomte C, Dahaoui S, Gillet JM, Souhassou M. Spin resolved electron density study of YTiO 3 in its ferromagnetic phase: signature of orbital ordering. IUCRJ 2019; 6:884-894. [PMID: 31576221 PMCID: PMC6760435 DOI: 10.1107/s2052252519009230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/27/2019] [Indexed: 06/10/2023]
Abstract
The present work reports on the charge and spin density modelling of YTiO3 in its ferromagnetic state (T C = 27 K). Accurate polarized neutron diffraction and high-resolution X-ray diffraction (XRD) experiments were carried out on a single crystal at the ORPHÉE reactor (LLB) and SPRING8 synchrotron source. The experimental data are modelled by the spin resolved pseudo-atomic multipolar model (Deutsch et al., 2012 ▸). The refinement strategy is discussed and the result of this electron density modelling is compared with that from XRD measured at 100 K and with density functional theory calculations. The results show that the spin and charge densities around the Ti atom have lobes directed away from the O atoms, confirming the filling of the t 2g orbitals of the Ti atom. The d xy orbital is less populated than d xz and d yz , which is a sign of a partial lift of degeneracy of the t 2g orbitals. This study confirms the orbital ordering at low temperature (20 K), which is already present in the paramagnetic state above the ferromagnetic transition (100 K).
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Affiliation(s)
- Ariste Bolivard Voufack
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Iurii Kibalin
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- PNPI NRC, Kurcharov Institut, Orlova Rosha, Gatchina, Leningrad region 188300, Russian Federation
| | - Zeyin Yan
- CentraleSupelec, Grande Voie des Vignes, 92295 Chatenay-Malabry Cedex, France
| | - Nicolas Claiser
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Saber Gueddida
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Béatrice Gillon
- LLB, CEA-CNRS, UMR 12, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Florence Porcher
- LLB, CEA-CNRS, UMR 12, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Arsen Gukasov
- LLB, CEA-CNRS, UMR 12, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Kunishisa Sugimoto
- SPring-8, Japan Synchrtron Radiation Research Institut, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Claude Lecomte
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Slimane Dahaoui
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Jean-Michel Gillet
- SPMS, UMR 8580, CentraleSupelec, Paris Saclay University, 91191 Gif-sur-Yvette, France
| | - Mohamed Souhassou
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
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5
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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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6
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Huang Z, Mongan S, Datta T, Yao DX. Indirect K-edge bimagnon resonant inelastic x-ray scattering spectrum of α-FeTe. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:505802. [PMID: 29125474 DOI: 10.1088/1361-648x/aa99c5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We calculate the K-edge indirect bimagnon resonant inelastic x-ray scattering (RIXS) intensity spectra of the bicollinear antiferromagnetic order known to occur in the α-FeTe chalcogenide system. Utilizing linear spin wave theory for this large-S spin system we find that the bimagnon spectrum contains four scattering channels (two intraband and two interband). We find from our calculations that for suitable energy-momentum combination the RIXS spectra can exhibit a one-, two- or three- peak structure. The number of peaks provides a clue on the various bimagnon excitation processes that can be supported both in and within the acoustic and optical magnon branches of the bicollinear antiferromagnet. Unlike the RIXS response of the antiferromagnetic or the collinear antiferromagnetic spin ordering, the RIXS intensity spectrum of the bicollinear antiferromagnet does not vanish at the magnetic ordering wave vector [Formula: see text]. It is also sensitive to next-next nearest neighbor and biquadratic coupling interactions. Our predicted RIXS spectrum can be utilized to understand the role of multi-channel bimagnon spin excitations present in the α-FeTe chalcogenide.
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Affiliation(s)
- Zengye Huang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, People's Republic of China
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7
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Bogdanov NA, Bisogni V, Kraus R, Monney C, Zhou K, Schmitt T, Geck J, Mitrushchenkov AO, Stoll H, van den Brink J, Hozoi L. Orbital breathing effects in the computation of x-ray d-ion spectra in solids by ab initio wave-function-based methods. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:035502. [PMID: 27869641 DOI: 10.1088/1361-648x/29/3/035502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In existing theoretical approaches to core-level excitations of transition-metal ions in solids relaxation and polarization effects due to the inner core hole are often ignored or described phenomenologically. Here we set up an ab initio computational scheme that explicitly accounts for such physics in the calculation of x-ray absorption and resonant inelastic x-ray scattering spectra. Good agreement is found with experimental transition-metal L-edge data for the strongly correlated d 9 cuprate Li2CuO2, for which we determine the absolute scattering intensities. The newly developed methodology opens the way for the investigation of even more complex d n electronic structures of group VI B to VIII B correlated oxide compounds.
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Affiliation(s)
- Nikolay A Bogdanov
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany. Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
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8
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Marra P, van den Brink J, Sykora S. Theoretical approach to resonant inelastic x-ray scattering in iron-based superconductors at the energy scale of the superconducting gap. Sci Rep 2016; 6:25386. [PMID: 27151253 PMCID: PMC4858731 DOI: 10.1038/srep25386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/04/2016] [Indexed: 11/09/2022] Open
Abstract
We develop a phenomenological theory to predict the characteristic features of the momentum-dependent scattering amplitude in resonant inelastic x-ray scattering (RIXS) at the energy scale of the superconducting gap in iron-based super-conductors. Taking into account all relevant orbital states as well as their specific content along the Fermi surface we evaluate the charge and spin dynamical structure factors for the compounds LaOFeAs and LiFeAs, based on tight-binding models which are fully consistent with recent angle-resolved photoemission spectroscopy (ARPES) data. We find a characteristic intensity redistribution between charge and spin dynamical structure factors which discriminates between sign-reversing and sign-preserving quasiparticle excitations. Consequently, our results show that RIXS spectra can distinguish between s± and s++ wave gap functions in the singlet pairing case. In addition, we find that an analogous intensity redistribution at small momenta can reveal the presence of a chiral p-wave triplet pairing.
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Affiliation(s)
- Pasquale Marra
- CNR-SPIN Salerno, I-84084 Fisciano (Salerno), Italy
- Department of Physics “E. R. Caianiello”, University of Salerno, I-84084 Fisciano (Salerno), Italy
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany
| | - Jeroen van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany
- Department of Physics, TU Dresden, D-01062 Dresden, Germany
| | - Steffen Sykora
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany
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9
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Ulrich C, Khaliullin G, Guennou M, Roth H, Lorenz T, Keimer B. Spin-Orbital Excitation Continuum and Anomalous Electron-Phonon Interaction in the Mott Insulator LaTiO_{3}. PHYSICAL REVIEW LETTERS 2015; 115:156403. [PMID: 26550738 DOI: 10.1103/physrevlett.115.156403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Indexed: 06/05/2023]
Abstract
Raman scattering experiments on stoichiometric, Mott-insulating LaTiO_{3} over a wide range of excitation energies reveal a broad electronic continuum which is featureless in the paramagnetic state, but develops a gap of ~800 cm^{-1} upon cooling below the Néel temperature T_{N}=146 K. In the antiferromagnetic state, the spectral weight below the gap is transferred to well-defined spectral features due to spin and orbital excitations. Low-energy phonons exhibit pronounced Fano anomalies indicative of strong interaction with the electron system for T>T_{N}, but become sharp and symmetric for T<T_{N}. The electronic continuum and the marked renormalization of the phonon lifetime by the onset of magnetic order are highly unusual for Mott insulators and indicate liquidlike correlations between spins and orbitals.
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Affiliation(s)
- C Ulrich
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - G Khaliullin
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - M Guennou
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - H Roth
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany
| | - T Lorenz
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
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10
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Laverock J, Chen B, Preston ARH, Newby D, Piper LFJ, Tung LD, Balakrishnan G, Glans PA, Guo JH, Smith KE. Low-energy V t2g orbital excitations in NdVO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:455603. [PMID: 25336521 DOI: 10.1088/0953-8984/26/45/455603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The electronic structure of NdVO(3) and YVO(3) has been investigated as a function of sample temperature using resonant inelastic soft x-ray scattering at the V L(3)-edge. Most of the observed spectral features are in good agreement with an atomic crystal-field multiplet model. However, a low energy feature is observed at ∼ 0.4 eV that cannot be explained by crystal-field arguments. The resonant behaviour of this feature establishes it as due to excitations of the V t(2g) states. Moreover, this feature exhibits a strong sample temperature dependence, reaching maximum intensity in the orbitally-ordered phase of NdVO(3), before becoming suppressed at low temperatures. This behaviour indicates that the origin of this feature is a collective orbital excitation, i.e. the bi-orbiton.
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Affiliation(s)
- J Laverock
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
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11
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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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12
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Wang Y, Jia CJ, Moritz B, Devereaux TP. Real-space visualization of remnant Mott gap and magnon excitations. PHYSICAL REVIEW LETTERS 2014; 112:156402. [PMID: 24785060 DOI: 10.1103/physrevlett.112.156402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 06/03/2023]
Abstract
We demonstrate the ability to visualize real-space dynamics of charge gap and magnon excitations in the Mott phase of the single-band Hubbard model and the remnants of these excitations with hole or electron doping. At short times, the character of magnetic and charge excitations is maintained even for large doping away from the Mott and antiferromagnetic phases. Doping influences both the real-space patterns and long timescales of these excitations with a clear carrier asymmetry attributable to particle-hole symmetry breaking in the underlying model. Further, a rapidly oscillating charge-density-wave-like pattern weakens, but persists as a visible demonstration of a subleading instability at half-filling which remains upon doping. The results offer an approach to analyzing the behavior of systems where momentum space is either inaccessible or poorly defined.
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Affiliation(s)
- Y Wang
- Department of Applied Physics, Stanford University, California 94305, USA and SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - C J Jia
- Department of Applied Physics, Stanford University, California 94305, USA and SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - B Moritz
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA and Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202, USA
| | - T P Devereaux
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, 2575 Sand Hill Road, Menlo Park, California 94025, USA and Geballe Laboratory for Advanced Materials, Stanford University, California 94305, USA
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13
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Marra P, Sykora S, Wohlfeld K, van den Brink J. Resonant inelastic x-ray scattering as a probe of the phase and excitations of the order parameter of superconductors. PHYSICAL REVIEW LETTERS 2013; 110:117005. [PMID: 25166567 DOI: 10.1103/physrevlett.110.117005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Indexed: 06/03/2023]
Abstract
The capability to probe the dispersion of elementary spin, charge, orbital, and lattice excitations has positioned resonant inelastic x-ray scattering (RIXS) at the forefront of photon science. Here we develop the scattering theory for RIXS on superconductors, calculating its momentum-dependent scattering amplitude. Considering superconductors with different pairing symmetries, we show that the low-energy scattering is strongly affected by the superconducting gap and coherence factors. This establishes RIXS as a tool to disentangle pairing symmetries and to probe the elementary excitations of unconventional superconductors.
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Affiliation(s)
- Pasquale Marra
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany
| | - Steffen Sykora
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany
| | - Krzysztof Wohlfeld
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany
| | - Jeroen van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany and Department of Physics, TU Dresden, D-01062 Dresden, Germany
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14
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Spin–orbital separation in the quasi-one-dimensional Mott insulator Sr2CuO3. Nature 2012; 485:82-5. [DOI: 10.1038/nature10974] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 02/17/2012] [Indexed: 11/09/2022]
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15
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Kavčič M, Budnar M, Mühleisen A, Gasser F, Žitnik M, Bučar K, Bohinc R. Design and performance of a versatile curved-crystal spectrometer for high-resolution spectroscopy in the tender x-ray range. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:033113. [PMID: 22462912 DOI: 10.1063/1.3697862] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A complete in-vacuum curved-crystal x-ray emission spectrometer in Johansson geometry has been constructed for a 2-6 keV energy range with sub natural line-width energy resolution. The spectrometer is designed to measure x-ray emission induced by photon and charged particle impact on solid and gaseous targets. It works with a relatively large x-ray source placed inside the Rowland circle and employs position sensitive detection of diffracted x-rays. Its compact modular design enables fast and easy installation at a synchrotron or particle accelerator beamline. The paper presents main characteristics of the spectrometer and illustrates its capabilities by showing few selected experimental examples.
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Affiliation(s)
- M Kavčič
- J. Stefan Institute, Jamova 39, SI-1001, Ljubljana, Slovenia.
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16
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Harada Y, Kobayashi M, Niwa H, Senba Y, Ohashi H, Tokushima T, Horikawa Y, Shin S, Oshima M. Ultrahigh resolution soft x-ray emission spectrometer at BL07LSU in SPring-8. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:013116. [PMID: 22299938 DOI: 10.1063/1.3680559] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An extremely high resolution flat field type slit less soft x-ray emission spectrometer has been designed and constructed for the long undulator beamline BL07LSU in SPring-8. By optimizing the ruling parameters of two cylindrical gratings, a high energy resolution ΔE < 100 meV and/or an E∕ΔE ~ 10 000 are expected for the energy range of 350 eV - 750 eV taking into account the broadening by the spatial resolution (25 μm) of a CCD detector. A coma-free operation mode proposed by Strocov et al., is also applied to eliminate both defocus and coma aberrations. The spectrometer demonstrated experimentally that E/ΔE = 10 050 and 8046 for N 1s (402.1 eV) and Mn 2p (641.8 eV) edges, respectively.
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Affiliation(s)
- Yoshihisa Harada
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Bunkyo, Tokyo, Japan.
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Wohlfeld K, Daghofer M, Nishimoto S, Khaliullin G, van den Brink J. Intrinsic coupling of orbital excitations to spin fluctuations in Mott insulators. PHYSICAL REVIEW LETTERS 2011; 107:147201. [PMID: 22107231 DOI: 10.1103/physrevlett.107.147201] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Indexed: 05/31/2023]
Abstract
We show how the general and basic asymmetry between two fundamental degrees of freedom present in strongly correlated oxides, spin and orbital, has very profound repercussions on the elementary spin and orbital excitations. Whereas the magnons remain largely unaffected, orbitons become inherently coupled with spin fluctuations in spin-orbital models with antiferromagnetic and ferro-orbital ordered ground states. The composite orbiton-magnon modes that emerge fractionalize again in one dimension, giving rise to spin-orbital separation in the peculiar regime where spinons are faster than orbitons.
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18
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Glawion S, Heidler J, Haverkort MW, Duda LC, Schmitt T, Strocov VN, Monney C, Zhou KJ, Ruff A, Sing M, Claessen R. Two-spinon and orbital excitations of the spin-Peierls system TiOCl. PHYSICAL REVIEW LETTERS 2011; 107:107402. [PMID: 21981527 DOI: 10.1103/physrevlett.107.107402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 05/04/2011] [Indexed: 05/31/2023]
Abstract
We combine high-resolution resonant inelastic x-ray scattering with cluster calculations utilizing a recently derived effective magnetic scattering operator to analyze the polarization, excitation energy, and momentum-dependent excitation spectrum of the low-dimensional quantum magnet TiOCl in the range expected for orbital and magnetic excitations (0-2.5 eV). Ti 3d orbital excitations yield complete information on the temperature-dependent crystal-field splitting. In the spin-Peierls phase we observe a dispersive two-spinon excitation and estimate the inter- and intradimer magnetic exchange coupling from a comparison to cluster calculations.
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Affiliation(s)
- S Glawion
- Experimentelle Physik 4, Universität Würzburg, 97074 Würzburg, Germany
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Garcia-Barriocanal J, Cezar J, Bruno F, Thakur P, Brookes N, Utfeld C, Rivera-Calzada A, Giblin S, Taylor J, Duffy J, Dugdale S, Nakamura T, Kodama K, Leon C, Okamoto S, Santamaria J. Spin and orbital Ti magnetism at LaMnO3/SrTiO3 interfaces. Nat Commun 2010; 1:82. [DOI: 10.1038/ncomms1080] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 08/24/2010] [Indexed: 11/09/2022] Open
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