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Liu R, Zhang W, Wei Y, Tao Z, Asmara TC, Li Y, Strocov VN, Yu R, Si Q, Schmitt T, Lu X. Nematic Spin Correlations Pervading the Phase Diagram of FeSe_{1-x}S_{x}. Phys Rev Lett 2024; 132:016501. [PMID: 38242670 DOI: 10.1103/physrevlett.132.016501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 12/08/2023] [Indexed: 01/21/2024]
Abstract
We use resonant inelastic x-ray scattering (RIXS) at the Fe-L_{3} edge to study the spin excitations of uniaxial-strained and unstrained FeSe_{1-x}S_{x} (0≤x≤0.21) samples. The measurements on unstrained samples reveal dispersive spin excitations in all doping levels, which show only minor doping dependence in energy dispersion, lifetime, and intensity, indicating that high-energy spin excitations are only marginally affected by sulfur doping. RIXS measurements on uniaxial-strained samples reveal that the high-energy spin-excitation anisotropy observed previously in FeSe is also present in the doping range 0200 K in x=0.18 and reaches a maximum around the nematic quantum critical doping (x_{c}≈0.17). Since the spin-excitation anisotropy directly reflects the existence of nematic spin correlations, our results indicate that high-energy nematic spin correlations pervade the regime of nematicity in the phase diagram and are enhanced by the nematic quantum criticality. These results emphasize the essential role of spin fluctuations in driving electronic nematicity and highlight the capability of uniaxial strain in tuning spin excitations in quantum materials hosting strong magnetoelastic coupling and electronic nematicity.
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Affiliation(s)
- Ruixian Liu
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Wenliang Zhang
- Photon Science Division, Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Yuan Wei
- Photon Science Division, Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Zhen Tao
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
- Photon Science Division, Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Teguh C Asmara
- Photon Science Division, Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- European X-Ray Free-Electron Laser Facility GmbH, 22869 Schenefeld, Germany
| | - Yi Li
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Vladimir N Strocov
- Photon Science Division, Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Rong Yu
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Thorsten Schmitt
- Photon Science Division, Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Xingye Lu
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
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2
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Occhialini CA, Sanchez JJ, Song Q, Fabbris G, Choi Y, Kim JW, Ryan PJ, Comin R. Spontaneous orbital polarization in the nematic phase of FeSe. Nat Mater 2023; 22:985-991. [PMID: 37349393 DOI: 10.1038/s41563-023-01585-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 05/19/2023] [Indexed: 06/24/2023]
Abstract
The origin of nematicity in FeSe remains a critical outstanding question towards understanding unconventional superconductivity in proximity to nematic order. To understand what drives the nematicity, it is essential to determine which electronic degree of freedom admits a spontaneous order parameter independent from the structural distortion. Here we use X-ray linear dichroism at the Fe K pre-edge to measure the anisotropy of the 3d orbital occupation as a function of in situ applied stress and temperature across the nematic transition. Along with using X-ray diffraction to precisely quantify the strain state, we reveal a lattice-independent, spontaneously ordered orbital polarization within the nematic phase, as well as an orbital polarizability that diverges as the transition is approached from above. These results provide strong evidence that spontaneous orbital polarization serves as the primary order parameter of the nematic phase.
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Affiliation(s)
- Connor A Occhialini
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Joshua J Sanchez
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Qian Song
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gilberto Fabbris
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Yongseong Choi
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Philip J Ryan
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
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3
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Abstract
Detection of AC magnetic fields at the nanoscale is critical in applications ranging from fundamental physics to materials science. Isolated quantum spin defects, such as the nitrogen-vacancy center in diamond, can achieve the desired spatial resolution with high sensitivity. Still, vector AC magnetometry currently relies on using different orientations of an ensemble of sensors, with degraded spatial resolution, and a protocol based on a single NV is lacking. Here we propose and experimentally demonstrate a protocol that exploits a single NV to reconstruct the vectorial components of an AC magnetic field by tuning a continuous driving to distinct resonance conditions. We map the spatial distribution of an AC field generated by a copper wire on the surface of the diamond. The proposed protocol combines high sensitivity, broad dynamic range, and sensitivity to both coherent and stochastic signals, with broad applications in condensed matter physics, such as probing spin fluctuations.
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Affiliation(s)
- Guoqing Wang
- Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yi-Xiang Liu
- Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yuan Zhu
- Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Paola Cappellaro
- Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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4
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Pelliciari J, Karakuzu S, Song Q, Arpaia R, Nag A, Rossi M, Li J, Yu T, Chen X, Peng R, García-Fernández M, Walters AC, Wang Q, Zhao J, Ghiringhelli G, Feng D, Maier TA, Zhou KJ, Johnston S, Comin R. Evolution of spin excitations from bulk to monolayer FeSe. Nat Commun 2021; 12:3122. [PMID: 34035254 DOI: 10.1038/s41467-021-23317-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 04/16/2021] [Indexed: 11/24/2022] Open
Abstract
In ultrathin films of FeSe grown on SrTiO3 (FeSe/STO), the superconducting transition temperature Tc is increased by almost an order of magnitude, raising questions on the pairing mechanism. As in other superconductors, antiferromagnetic spin fluctuations have been proposed to mediate SC making it essential to study the evolution of the spin dynamics of FeSe from the bulk to the ultrathin limit. Here, we investigate the spin excitations in bulk and monolayer FeSe/STO using resonant inelastic x-ray scattering (RIXS) and quantum Monte Carlo (QMC) calculations. Despite the absence of long-range magnetic order, bulk FeSe displays dispersive magnetic excitations reminiscent of other Fe-pnictides. Conversely, the spin excitations in FeSe/STO are gapped, dispersionless, and significantly hardened relative to its bulk counterpart. By comparing our RIXS results with simulations of a bilayer Hubbard model, we connect the evolution of the spin excitations to the Fermiology of the two systems revealing a remarkable reconfiguration of spin excitations in FeSe/STO, essential to understand the role of spin fluctuations in the pairing mechanism. Here, Pelliciari et al. present resonant inelastic X-ray scattering on monolayer samples of unconventional superconductor FeSe, finding evidence for gapped and dispersionless spin excitations. These experiments are very difficult due to the extremely small scattering volume of the FeSe monolayer.
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5
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Butler KT, Le MD, Thiyagalingam J, Perring TG. Interpretable, calibrated neural networks for analysis and understanding of inelastic neutron scattering data. J Phys Condens Matter 2021; 33:194006. [PMID: 33635282 DOI: 10.1088/1361-648x/abea1c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Deep neural networks (NNs) provide flexible frameworks for learning data representations and functions relating data to other properties and are often claimed to achieve 'super-human' performance in inferring relationships between input data and desired property. In the context of inelastic neutron scattering experiments, however, as in many other scientific scenarios, a number of issues arise: (i) scarcity of labelled experimental data, (ii) lack of uncertainty quantification on results, and (iii) lack of interpretability of the deep NNs. In this work we examine approaches to all three issues. We use simulated data to train a deep NN to distinguish between two possible magnetic exchange models of a half-doped manganite. We apply the recently developed deterministic uncertainty quantification method to provide error estimates for the classification, demonstrating in the process how important realistic representations of instrument resolution in the training data are for reliable estimates on experimental data. Finally we use class activation maps to determine which regions of the spectra are most important for the final classification result reached by the network.
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Affiliation(s)
- Keith T Butler
- SciML, Scientific Computing Department, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, United Kingdom
- Department of Materials Science and Engineering, University of Oxford, 21 Banbury Rd, Oxford OX2 6HT, United Kingdom
| | - Manh Duc Le
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, United Kingdom
| | - Jeyan Thiyagalingam
- SciML, Scientific Computing Department, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, United Kingdom
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, United Kingdom
| | - Toby G Perring
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, United Kingdom
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Abstract
Emergent electronic phenomena in iron-based superconductors have been at the forefront of condensed matter physics for more than a decade. Much has been learned about the origins and intertwined roles of ordered phases, including nematicity, magnetism, and superconductivity, in this fascinating class of materials. In recent years, focus has been centered on the peculiar and highly unusual properties of FeSe and its close cousins. This family of materials has attracted considerable attention due to the discovery of unexpected superconducting gap structures, a wide range of superconducting critical temperatures, and evidence for nontrivial band topology, including associated spin-helical surface states and vortex-induced Majorana bound states. Here, we review superconductivity in iron chalcogenide superconductors, including bulk FeSe, doped bulk FeSe, FeTe1−xSex, intercalated FeSe materials, and monolayer FeSe and FeTe1−xSex on SrTiO3. We focus on the superconducting properties, including a survey of the relevant experimental studies, and a discussion of the different proposed theoretical pairing scenarios. In the last part of the paper, we review the growing recent evidence for nontrivial topological effects in FeSe-related materials, focusing again on interesting implications for superconductivity.
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7
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Hong X, Caglieris F, Kappenberger R, Wurmehl S, Aswartham S, Scaravaggi F, Lepucki P, Wolter AUB, Grafe HJ, Büchner B, Hess C. Evolution of the Nematic Susceptibility in LaFe_{1-x}Co_{x}AsO. Phys Rev Lett 2020; 125:067001. [PMID: 32845654 DOI: 10.1103/physrevlett.125.067001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 06/26/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
We report a systematic elastoresistivity study on LaFe_{1-x}Co_{x}AsO single crystals, which have well separated structural and magnetic transition lines. All crystals show a Curie-Weiss-like nematic susceptibility in the tetragonal phase. The extracted nematic temperature is monotonically suppressed upon cobalt doping, and changes sign around the optimal doping level, indicating a possible nematic quantum critical point beneath the superconducting dome. The amplitude of the nematic susceptibility shows a peculiar double-peak feature. This could be explained by a combined effect of different contributions to the nematic susceptibility, which are amplified at separated doping levels of LaFe_{1-x}Co_{x}AsO.
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Affiliation(s)
- Xiaochen Hong
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Federico Caglieris
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Rhea Kappenberger
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Sabine Wurmehl
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Saicharan Aswartham
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Francesco Scaravaggi
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
- Institute of Solid State and Materials Physics, Technische Universität Dresden, 01069 Dresden, Germany
| | - Piotr Lepucki
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Anja U B Wolter
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Hans-Joachim Grafe
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
| | - Bernd Büchner
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
- Institute of Solid State and Materials Physics, Technische Universität Dresden, 01069 Dresden, Germany
- Center for Transport and Devices, Technische Universität Dresden, 01069 Dresden, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Christian Hess
- Leibniz-Institute for Solid State and Materials Research (IFW Dresden), 01069 Dresden, Germany
- Center for Transport and Devices, Technische Universität Dresden, 01069 Dresden, Germany
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8
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Udina M, Grilli M, Benfatto L, Chubukov AV. Raman Response in the Nematic Phase of FeSe. Phys Rev Lett 2020; 124:197602. [PMID: 32469539 DOI: 10.1103/physrevlett.124.197602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/21/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
Raman experiments on bulk FeSe revealed that the low-frequency part of the B_{1g} Raman response R_{B1g}(Ω), which probes nematic fluctuations, rapidly decreases below the nematic transition at T_{n}∼85 K. Such behavior is expected when a gap opens up and at a first glance is inconsistent with the fact that FeSe remains a metal below T_{n}. We argue that the drop of R_{B1g}(Ω) can be ascribed to the fact that the nematic order drastically changes the orbital content of low-energy excitations near hole and electron pockets, making them nearly mono-orbital. In this situation, the B_{1g} Raman response gets reduced by the same vertex corrections that enforce charge conservation in the symmetric Raman channel. The reduction holds at low frequencies and gives rise to gaplike behavior of R_{B1g}(Ω). We also show that the enhancement of the B_{1g} Raman response near T_{n} is consistent with the sign change of the nematic order parameter between hole and electron pockets.
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Affiliation(s)
- Mattia Udina
- Department of Physics and ISC-CNR, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Marco Grilli
- Department of Physics and ISC-CNR, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Lara Benfatto
- Department of Physics and ISC-CNR, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Andrey V Chubukov
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
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9
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Merritt AM, Weber F, Castellan JP, Wolf T, Ishikawa D, Said AH, Alatas A, Fernandes RM, Baron AQR, Reznik D. Nematic Correlation Length in Iron-Based Superconductors Probed by Inelastic X-Ray Scattering. Phys Rev Lett 2020; 124:157001. [PMID: 32357044 DOI: 10.1103/physrevlett.124.157001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/19/2020] [Indexed: 06/11/2023]
Abstract
Nematicity is ubiquitous in electronic phases of high-T_{c} superconductors, particularly in the Fe-based systems. We used inelastic x-ray scattering to extract the temperature-dependent nematic correlation length ξ from the anomalous softening of acoustic phonon modes in FeSe, underdoped Ba(Fe_{0.97}Co_{0.03})_{2}As_{2}, and optimally doped Ba(Fe_{0.94}Co_{0.06})_{2}As_{2}. In all cases, we find that ξ is well described by a power law (T-T_{0})^{-1/2} extending over a wide temperature range. Combined with the previously reported Curie-Weiss behavior of the nematic susceptibility, these results point to the mean-field character of the nematic transition, which we attribute to a sizable nematoelastic coupling that is likely detrimental to superconductivity.
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Affiliation(s)
- A M Merritt
- Department of Physics, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - F Weber
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - J-P Castellan
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- CEA Saclay, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette, France
| | - Th Wolf
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - D Ishikawa
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo, Hyogo 679-5148 Japan
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Alatas
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - A Q R Baron
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo, Hyogo 679-5148 Japan
| | - D Reznik
- Department of Physics, University of Colorado at Boulder, Boulder, Colorado 80309, USA
- Center for Experiments on Quantum Materials, University of Colorado at Boulder, Boulder, Colorado 80309, USA
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10
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Song SY, Martiny JHJ, Kreisel A, Andersen BM, Seo J. Visualization of Local Magnetic Moments Emerging from Impurities in Hund's Metal States of FeSe. Phys Rev Lett 2020; 124:117001. [PMID: 32242691 DOI: 10.1103/physrevlett.124.117001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/30/2019] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
Understanding the origin of the magnetism of high temperature superconductors is crucial for establishing their unconventional pairing mechanism. Recently, theory predicts that FeSe is close to a magnetic quantum critical point, and thus weak perturbations such as impurities could induce local magnetic moments. To elucidate such quantum instability, we have employed scanning tunneling microscopy and spectroscopy. In particular, we have grown FeSe film on superconducting Pb(111) using molecular beam epitaxy and investigated magnetic excitation caused by impurities in the proximity-induced superconducting gap of FeSe. Our study provides deep insight into the origin of the magnetic ordering of FeSe by showing the way local magnetic moments develop in response to impurities near the magnetic quantum critical point.
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Affiliation(s)
- Sang Yong Song
- Department of Emerging Materials Science, DGIST, 333 Techno-Jungang-daero, Hyeonpung-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - J H J Martiny
- Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - A Kreisel
- Institut für Theoretische Physik, Universität Leipzig, D-04103 Leipzig, Germany
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
| | - Jungpil Seo
- Department of Emerging Materials Science, DGIST, 333 Techno-Jungang-daero, Hyeonpung-Eup, Dalseong-Gun, Daegu 42988, Korea
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11
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Chen T, Chen Y, Tam DW, Gao B, Qiu Y, Schneidewind A, Radelytskyi I, Prokes K, Chi S, Matsuda M, Broholm C, Dai P. Anisotropic effect of a magnetic field on the neutron spin resonance in FeSe. Phys Rev B 2020; 101:10.1103/physrevb.101.140504. [PMID: 33655092 PMCID: PMC7918269 DOI: 10.1103/physrevb.101.140504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We use inelastic neutron scattering to study the effect of a magnetic field on the neutron spin resonance (E r = 3.6 meV) of superconducting FeSe (T c = 9 K). While a field aligned along the in-plane direction broadens and suppresses the resonance, a c-axis aligned field does so much more efficiently, consistent with the anisotropic field-induced suppression of the superfluid density from the heat capacity measurements. These results suggest that the resonance in FeSe is associated with the superconducting electrons arising from orbital selective quasiparticle excitations between the hole and electron Fermi surfaces.
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Affiliation(s)
- Tong Chen
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Youzhe Chen
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - David W. Tam
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Bin Gao
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Yiming Qiu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Astrid Schneidewind
- Jülich Center for Neutron Sciences, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
| | - Igor Radelytskyi
- Jülich Center for Neutron Sciences, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany
| | - Karel Prokes
- Helmholtz Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
| | - Songxue Chi
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Masaaki Matsuda
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Collin Broholm
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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12
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Pfau H, Chen SD, Yi M, Hashimoto M, Rotundu CR, Palmstrom JC, Chen T, Dai PC, Straquadine J, Hristov A, Birgeneau RJ, Fisher IR, Lu D, Shen ZX. Momentum Dependence of the Nematic Order Parameter in Iron-Based Superconductors. Phys Rev Lett 2019; 123:066402. [PMID: 31491189 DOI: 10.1103/physrevlett.123.066402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Indexed: 06/10/2023]
Abstract
The momentum dependence of the nematic order parameter is an important ingredient in the microscopic description of iron-based high-temperature superconductors. While recent reports on FeSe indicate that the nematic order parameter changes sign between electron and hole bands, detailed knowledge is still missing for other compounds. Combining angle-resolved photoemission spectroscopy with uniaxial strain tuning, we measure the nematic band splitting in both FeSe and BaFe_{2}As_{2} without interference from either twinning or magnetic order. We find that the nematic order parameter exhibits the same momentum dependence in both compounds with a sign change between the Brillouin center and the corner. This suggests that the same microscopic mechanism drives the nematic order in spite of the very different phase diagrams.
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Affiliation(s)
- H Pfau
- Stanford Institute of Materials and Energy Sience, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - S D Chen
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, 94305 California, USA
| | - M Yi
- Department of Physics, University of California, Berkeley, 94720 California, USA
- Department of Physics and Astronomy, Rice University, Houston, 77005 Texas, USA
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Acelerator Laboratory, Menlo Park, 94025 California, USA
| | - C R Rotundu
- Stanford Institute of Materials and Energy Sience, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J C Palmstrom
- Stanford Institute of Materials and Energy Sience, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, 94305 California, USA
| | - T Chen
- Department of Physics and Astronomy, Rice University, Houston, 77005 Texas, USA
| | - P-C Dai
- Department of Physics and Astronomy, Rice University, Houston, 77005 Texas, USA
| | - J Straquadine
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, 94305 California, USA
| | - A Hristov
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, 94305 California, USA
| | - R J Birgeneau
- Department of Physics, University of California, Berkeley, 94720 California, USA
| | - I R Fisher
- Stanford Institute of Materials and Energy Sience, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, 94305 California, USA
| | - D Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Acelerator Laboratory, Menlo Park, 94025 California, USA
| | - Z-X Shen
- Stanford Institute of Materials and Energy Sience, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, 94305 California, USA
- Department of Physics, Stanford University, Stanford, 94305 California, USA
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