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Yan H, Bok JM, He J, Zhang W, Gao Q, Luo X, Cai Y, Peng Y, Meng J, Li C, Chen H, Song C, Yin C, Miao T, Chen Y, Gu G, Lin C, Zhang F, Yang F, Zhang S, Peng Q, Liu G, Zhao L, Choi HY, Xu Z, Zhou XJ. Ubiquitous coexisting electron-mode couplings in high-temperature cuprate superconductors. Proc Natl Acad Sci U S A 2023; 120:e2219491120. [PMID: 37851678 PMCID: PMC10614907 DOI: 10.1073/pnas.2219491120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 09/12/2023] [Indexed: 10/20/2023] Open
Abstract
In conventional superconductors, electron-phonon coupling plays a dominant role in generating superconductivity. In high-temperature cuprate superconductors, the existence of electron coupling with phonons and other boson modes and its role in producing high-temperature superconductivity remain unclear. The evidence of electron-boson coupling mainly comes from angle-resolved photoemission (ARPES) observations of [Formula: see text]70-meV nodal dispersion kink and [Formula: see text]40-meV antinodal kink. However, the reported results are sporadic and the nature of the involved bosons is still under debate. Here we report findings of ubiquitous two coexisting electron-mode couplings in cuprate superconductors. By taking ultrahigh-resolution laser-based ARPES measurements, we found that the electrons are coupled simultaneously with two sharp modes at [Formula: see text]70meV and [Formula: see text]40meV in different superconductors with different dopings, over the entire momentum space and at different temperatures above and below the superconducting transition temperature. These observations favor phonons as the origin of the modes coupled with electrons and the observed electron-mode couplings are unusual because the associated energy scales do not exhibit an obvious energy shift across the superconducting transition. We further find that the well-known "peak-dip-hump" structure, which has long been considered a hallmark of superconductivity, is also omnipresent and consists of "peak-double dip-double hump" finer structures that originate from electron coupling with two sharp modes. These results provide a unified picture for the [Formula: see text]70-meV and [Formula: see text]40-meV energy scales and their evolutions with momentum, doping and temperature. They provide key information to understand the origin of these energy scales and their role in generating anomalous normal state and high-temperature superconductivity.
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Affiliation(s)
- Hongtao Yan
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Jin Mo Bok
- Department of Physics, Pohang University of Science and Technology, Pohang37673, Korea
| | - Junfeng He
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Wentao Zhang
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Qiang Gao
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Xiangyu Luo
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yongqing Cai
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Yingying Peng
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Jianqiao Meng
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Cong Li
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Hao Chen
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Chunyao Song
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Chaohui Yin
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Taimin Miao
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yiwen Chen
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Genda Gu
- Condensed Matter Physics, Materials Science Division of Brookhaven National Laboratory, Upton, NY11973-5000
| | - Chengtian Lin
- Max Planck Institute for Solid State Research, D-70569Stuttgart, Germany
| | - Fengfeng Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Guodong Liu
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
| | - Lin Zhao
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
| | - Han-Yong Choi
- Department of Physics, Sungkyunkwan University, Suwon16419, Korea
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - X. J. Zhou
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
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Hwang J. Analysis of optical data using extended Drude model and generalized Allen's formulas. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:405604. [PMID: 30160241 DOI: 10.1088/1361-648x/aaddca] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Extended Drude model formalism has been successfully utilized for analyzing optical spectra of strongly correlated electron systems including heavy-fermion systems and high-T c superconducting iron pnictides and cuprates. Furthermore, generalized Allen's formulas have been developed and applied to extract the electron-boson spectral density function from measured optical data of high temperature superconductors including cuprates in various material phases. Here we used a reverse process to obtain various optical quantities starting from two typical electron-boson spectral density model functions for three intriguing (normal, pseudogap, and d-wave superconducting) material phases in cuprates. We also assigned the calculated optical results to designated regions in the phase diagram of hole-doped cuprates and compared them with the corresponding measured optical spectra of Bi2Sr2CaCu2 [Formula: see text] (Bi-2212). This comparison suggested that this way of optical data analysis can be a convincing method to study correlated electrons in the copper oxide superconductors and other superconducting systems as well.
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Affiliation(s)
- Jungseek Hwang
- Department of Physics, Sungkyunkwan University, Suwon, Gyeonggi-do 16419, Republic of Korea. Photon Sciences, Brookhaven National Laboratory, Upton, NY 11973, United States of America
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3
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Li JJ, Zhang FF, Wang ZM, Xu YC, Liu XC, Zong N, Zhang SJ, Xu FL, Yang F, Yuan L, Kou Y, Bo Y, Cui DF, Peng QJ, Wang XY, Liu LJ, Chen CT, Xu ZY. High-energy single-frequency 167 nm deep-ultraviolet laser. OPTICS LETTERS 2018; 43:2563-2566. [PMID: 29856430 DOI: 10.1364/ol.43.002563] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 04/29/2018] [Indexed: 05/26/2023]
Abstract
We report a high-energy single-frequency deep-ultraviolet (DUV) solid-state laser at 167.079 nm by the eighth-harmonic generation of a diode-pumped Nd:LGGG laser. A maximum DUV laser output energy of 1.5 μJ at a 5 Hz repetition rate with a 200 μs pulse duration is achieved. The central wavelength of the DUV laser is located at 167.079 nm and can be finely tuned from 167.075 to 167.083 nm. The linewidth is estimated to be 0.025 pm. To the best of our knowledge, this is the first Letter reporting a high-energy single-frequency solid-state DUV laser below 170 nm. The successful demonstration of the high-energy single-frequency DUV laser source with the unique wavelength is useful for direct detection of a Al+27 ion via resonance fluorescence in a multi-ion optical clock.
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A New Landscape of Multiple Dispersion Kinks in a High-T c Cuprate Superconductor. Sci Rep 2017; 7:4830. [PMID: 28684868 PMCID: PMC5500550 DOI: 10.1038/s41598-017-04983-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 05/23/2017] [Indexed: 11/08/2022] Open
Abstract
Conventional superconductivity is caused by electron-phonon coupling. The discovery of high-temperature superconductors raised the question of whether such strong electron-phonon coupling is realized in cuprates. Strong coupling with some collective excitation mode has been indicated by a dispersion “kink”. However, there is intensive debate regarding whether the relevant coupling mode is a magnetic resonance mode or an oxygen buckling phonon mode. This ambiguity is a consequence of the energy of the main prominent kink. Here, we show a new landscape of dispersion kinks. We report that heavily overdoping a Bi2Sr2CaCu2O8+δ superconductor results in a decline of the conventional main kink and a rise of another sharp kink, along with substantial energy shifts of both. Notably, the latter kink can be ascribed only to an oxygen-breathing phonon. Hence, the multiple phonon branches provide a consistent account of our data set on the multiple kinks. Our results suggest that strong electron-phonon coupling and its dramatic change should be incorporated into or reconciled with scenarios for the evolution of high-Tc superconductivity.
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5
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In situ carrier tuning in high temperature superconductor Bi2Sr2CaCu2O8+ by potassium deposition. Sci Bull (Beijing) 2016. [DOI: 10.1007/s11434-016-1106-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Guo S, Liu L, Xia M, Kang L, Huang Q, Li C, Wang X, Lin Z, Chen C. Be2BO3F: A Phase of Beryllium Fluoride Borate Derived from KBe2BO3F2 with Short UV Absorption Edge. Inorg Chem 2016; 55:6586-91. [DOI: 10.1021/acs.inorgchem.6b00755] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shu Guo
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Lijuan Liu
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Mingjun Xia
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Lei Kang
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Qian Huang
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Chao Li
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Xiaoyang Wang
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zheshuai Lin
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chuangtian Chen
- Beijing
Center for Crystal Research and Development, Key Laboratory of Functional
Crystals and Laser Technology, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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7
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Affiliation(s)
- Qi-Kun Xue
- Department of Physics at Tsinghua University, Beijing 100084, China
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8
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Bok JM, Bae JJ, Choi HY, Varma CM, Zhang W, He J, Zhang Y, Yu L, Zhou XJ. Quantitative determination of pairing interactions for high-temperature superconductivity in cuprates. SCIENCE ADVANCES 2016; 2:e1501329. [PMID: 26973872 PMCID: PMC4783123 DOI: 10.1126/sciadv.1501329] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/05/2016] [Indexed: 06/05/2023]
Abstract
A profound problem in modern condensed matter physics is discovering and understanding the nature of fluctuations and their coupling to fermions in cuprates, which lead to high-temperature superconductivity and the invariably associated strange metal state. We report the quantitative determination of normal and pairing self-energies, made possible by laser-based angle-resolved photoemission measurements of unprecedented accuracy and stability. Through a precise inversion procedure, both the effective interactions in the attractive d-wave symmetry and the repulsive part in the full symmetry are determined. The latter is nearly angle-independent. Near T c, both interactions are nearly independent of frequency and have almost the same magnitude over the complete energy range of up to about 0.4 eV, except for a low-energy feature at around 50 meV that is present only in the repulsive part, which has less than 10% of the total spectral weight. Well below T c, they both change similarly, with superconductivity-induced features at low energies. Besides finding the pairing self-energy and the attractive interactions for the first time, these results expose the central paradox of the problem of high T c: how the same frequency-independent fluctuations can dominantly scatter at angles ±π/2 in the attractive channel to give d-wave pairing and lead to angle-independent repulsive scattering. The experimental results are compared with available theoretical calculations based on antiferromagnetic fluctuations, the Hubbard model, and quantum-critical fluctuations of the loop-current order.
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Affiliation(s)
- Jin Mo Bok
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jong Ju Bae
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - Han-Yong Choi
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
- Asia Pacific Center for Theoretical Physics, Pohang 790-784, Korea
| | - Chandra M. Varma
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
| | - Wentao Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Department of Physics and Astronomy, Shanghai JiaoTong University, Shanghai 200240, China
| | - Junfeng He
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuxiao Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Li Yu
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X. J. Zhou
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
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9
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Ishida Y, Saitoh T, Mochiku T, Nakane T, Hirata K, Shin S. Quasi-particles ultrafastly releasing kink bosons to form Fermi arcs in a cuprate superconductor. Sci Rep 2016; 6:18747. [PMID: 26728626 PMCID: PMC4700524 DOI: 10.1038/srep18747] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/25/2015] [Indexed: 01/12/2023] Open
Abstract
In a conventional framework, superconductivity is lost at a critical temperature (Tc) because, at higher temperatures, gluing bosons can no longer bind two electrons into a Cooper pair. In high-Tc cuprates, it is still unknown how superconductivity vanishes at Tc. We provide evidence that the so-called ≲70-meV kink bosons that dress the quasi-particle excitations are playing a key role in the loss of superconductivity in a cuprate. We irradiated a 170-fs laser pulse on Bi2Sr2CaCu2O8+δ and monitored the responses of the superconducting gap and dressed quasi-particles by time- and angle-resolved photoemission spectroscopy. We observe an ultrafast loss of superconducting gap near the d-wave node, or light-induced Fermi arcs, which is accompanied by spectral broadenings and weight redistributions occurring within the kink binding energy. We discuss that the underlying mechanism of the spectral broadening that induce the Fermi arc is the undressing of quasi-particles from the kink bosons. The loss mechanism is beyond the conventional framework, and can accept the unconventional phenomena such as the signatures of Cooper pairs remaining at temperatures above Tc.
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Affiliation(s)
- Y Ishida
- ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
| | - T Saitoh
- ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
| | - T Mochiku
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - T Nakane
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - K Hirata
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - S Shin
- ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan.,CREST JST, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
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10
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Hwang J. Reverse process of usual optical analysis of boson-exchange superconductors: impurity effects on s- and d-wave superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:085701. [PMID: 25651193 DOI: 10.1088/0953-8984/27/8/085701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We performed a reverse process of the usual optical data analysis of boson-exchange superconductors. We calculated the optical self-energy from two (MMP and MMP+peak) input model electron-boson spectral density functions using Allen's formula for one normal and two (s- and d-wave) superconducting cases. We obtained the optical constants including the optical conductivity and the dynamic dielectric function from the optical self-energy using an extended Drude model, and finally calculated the reflectance spectrum. Furthermore, to investigate impurity effects on optical quantities we added various levels of impurities (from the clean to the dirty limit) in the optical self-energy and performed the same reverse process to obtain the optical conductivity, the dielectric function, and reflectance. From these optical constants obtained from the reverse process we extracted the impurity-dependent superfluid densities for two superconducting cases using two independent methods (the Ferrel-Glover-Tinkham sum rule and the extrapolation to zero frequency of -ϵ1(ω)ω(2)); we found that a certain level of impurities is necessary to get a good agreement on results obtained by the two methods. We observed that impurities give similar effects on various optical constants of s- and d-wave superconductors; the greater the impurities the more distinct the gap feature and the lower the superfluid density. However, the s-wave superconductor gives the superconducting gap feature more clearly than the d-wave superconductor because in the d-wave superconductors the optical quantities are averaged over the anisotropic Fermi surface. Our results supply helpful information to see how characteristic features of the electron-boson spectral function and the s- and d-wave superconducting gaps appear in various optical constants including raw reflectance spectrum. Our study may help with a thorough understanding of the usual optical analysis process. Further systematic study of experimental data collected at various conditions using the optical analysis process will help to reveal the origin of the mediated boson in the boson-exchange superconductors.
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Affiliation(s)
- Jungseek Hwang
- Department of Physics, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Korea
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11
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Hwang J, Carbotte JP, Min BH, Kwon YS, Timusk T. Electron-boson spectral density of LiFeAs obtained from optical data. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:055701. [PMID: 25612554 DOI: 10.1088/0953-8984/27/5/055701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We analyze existing optical data in the superconducting state of LiFeAs at T = 4 K, to recover its electron-boson spectral density. A maximum entropy technique is employed to extract the spectral density I(2)χ(ω) from the optical scattering rate. Care is taken to properly account for elastic impurity scattering which can importantly affect the optics in an s-wave superconductor, but does not eliminate the boson structure. We find a robust peak in I(2)χ(ω) centered about Ω(R) ≅ 8.0 meV or 5.3 k(B)Tc (with Tc = 17.6 K). Its position in energy agrees well with a similar structure seen in scanning tunneling spectroscopy (STS). There is also a peak in the inelastic neutron scattering (INS) data at this same energy. This peak is found to persist in the normal state at T = 23 K. There is evidence that the superconducting gap is anisotropic as was also found in low temperature angular resolved photoemission (ARPES) data.
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Affiliation(s)
- J Hwang
- Department of Physics, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Republic of Korea
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12
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Wang X, Liu L, Wang X, Bai L, Chen C. Growth and optical properties of the novel nonlinear optical crystal NaSr3Be3B3O9F4. CrystEngComm 2015. [DOI: 10.1039/c4ce02096k] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Ultrafast quenching of electron–boson interaction and superconducting gap in a cuprate superconductor. Nat Commun 2014; 5:4959. [DOI: 10.1038/ncomms5959] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 08/11/2014] [Indexed: 01/24/2023] Open
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14
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Hong SH, Bok JM, Zhang W, He J, Zhou XJ, Varma CM, Choi HY. Sharp low-energy feature in single-particle spectra due to forward scattering in d-wave cuprate superconductors. PHYSICAL REVIEW LETTERS 2014; 113:057001. [PMID: 25126930 DOI: 10.1103/physrevlett.113.057001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Indexed: 06/03/2023]
Abstract
There is an enormous interest in the renormalization of the quasiparticle (qp) dispersion relation of cuprate superconductors both below and above the critical temperature T_{c} because it enables the determination of the fluctuation spectrum to which the qp's are coupled. A remarkable discovery by angle-resolved photoemission spectroscopy (ARPES) is a sharp low-energy feature (LEF) in qp spectra well below the superconducting energy gap but with its energy increasing in proportion to T_{c} and its intensity increasing sharply below T_{c}. This unexpected feature needs to be reconciled with d-wave superconductivity. Here, we present a quantitative analysis of ARPES data from Bi_{2}Sr_{2}CaCu_{2}O_{8+δ} (Bi2212) using Eliashberg equations to show that the qp scattering rate due to the forward scattering impurities far from the Cu-O planes is modified by the energy gap below T_{c} and shows up as the LEF. This is also a necessary step to analyze ARPES data to reveal the spectrum of fluctuations promoting superconductivity.
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Affiliation(s)
- Seung Hwan Hong
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - Jin Mo Bok
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - Wentao Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Junfeng He
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X J Zhou
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - C M Varma
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Han-Yong Choi
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea and Asia Pacific Center for Theoretical Physics, Pohang 790-784, Korea
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15
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He J, Zhang W, Bok JM, Mou D, Zhao L, Peng Y, He S, Liu G, Dong X, Zhang J, Wen JS, Xu ZJ, Gu GD, Wang X, Peng Q, Wang Z, Zhang S, Yang F, Chen C, Xu Z, Choi HY, Varma CM, Zhou XJ. Coexistence of two sharp-mode couplings and their unusual momentum dependence in the superconducting state of Bi2Sr2CaCu2O(8+δ) revealed by laser-based angle-resolved photoemission. PHYSICAL REVIEW LETTERS 2013; 111:107005. [PMID: 25166699 DOI: 10.1103/physrevlett.111.107005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/12/2013] [Indexed: 06/03/2023]
Abstract
High-resolution laser-based angle-resolved photoemission measurements have been carried out on Bi2Sr2CaCu2O(8+δ) (Bi2212) superconductors to investigate momentum dependence of electron coupling with collective excitations (modes). Two coexisting energy scales are clearly revealed over a large momentum space for the first time in the superconducting state of the overdoped Bi2212 superconductor. These two energy scales exhibit distinct momentum dependence: one keeps its energy near 78 meV over a large momentum space while the other changes its energy from ∼40 meV near the antinodal region to ∼70 meV near the nodal region. These observations provide a new picture on momentum evolution of electron-boson coupling in Bi2212 that electrons are coupled with two sharp modes simultaneously over a large momentum space in the superconducting states. Their unusual momentum dependence poses a challenge to our current understanding of electron-mode-coupling and its role for high-temperature superconductivity in cuprate superconductors.
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Affiliation(s)
- Junfeng He
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Wentao Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Jin Mo Bok
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - Daixiang Mou
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Lin Zhao
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Yingying Peng
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Shaolong He
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Guodong Liu
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Xiaoli Dong
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Jun Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - J S Wen
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Z J Xu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Xiaoyang Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Zhimin Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Chuangtian Chen
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - H-Y Choi
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - C M Varma
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - X J Zhou
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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Gotlieb K, Hussain Z, Bostwick A, Lanzara A, Jozwiak C. Rapid high-resolution spin- and angle-resolved photoemission spectroscopy with pulsed laser source and time-of-flight spectrometer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:093904. [PMID: 24089838 DOI: 10.1063/1.4821247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A high-efficiency spin- and angle-resolved photoemission spectroscopy (spin-ARPES) spectrometer is coupled with a laboratory-based laser for rapid high-resolution measurements. The spectrometer combines time-of-flight (TOF) energy measurements with low-energy exchange scattering spin polarimetry for high detection efficiencies. Samples are irradiated with fourth harmonic photons generated from a cavity-dumped Ti:sapphire laser that provides high photon flux in a narrow bandwidth, with a pulse timing structure ideally matched to the needs of the TOF spectrometer. The overall efficiency of the combined system results in near-E(F) spin-resolved ARPES measurements with an unprecedented combination of energy resolution and acquisition speed. This allows high-resolution spin measurements with a large number of data points spanning multiple dimensions of interest (energy, momentum, photon polarization, etc.) and thus enables experiments not otherwise possible. The system is demonstrated with spin-resolved energy and momentum mapping of the L-gap Au(111) surface states, a prototypical Rashba system. The successful integration of the spectrometer with the pulsed laser system demonstrates its potential for simultaneous spin- and time-resolved ARPES with pump-probe based measurements.
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Affiliation(s)
- K Gotlieb
- Graduate Group in Applied Science and Technology, University of California, Berkeley, California 94720, USA
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Kondo T, Nakashima Y, Malaeb W, Ishida Y, Hamaya Y, Takeuchi T, Shin S. Anomalous doping variation of the nodal low-energy feature of superconducting (Bi,Pb)2(Sr,La)2CuO(6+δ) crystals revealed by laser-based angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2013; 110:217006. [PMID: 23745917 DOI: 10.1103/physrevlett.110.217006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Indexed: 06/02/2023]
Abstract
The nodal band dispersion in (Bi,Pb)(2)(Sr,La)(2)CuO(6+δ) (Bi2201) is investigated over a wide range of doping by using 7-eV laser-based angle-resolved photoemission spectroscopy. We find that the low-energy band renormalization ("kink"), recently discovered in Bi(2)Sr(2)CaCu(2)O(8+δ) (Bi2212), also occurs in Bi2201, but at a binding energy around half that in Bi2212. Surprisingly, the coupling energy dramatically increases with a decrease of carrier concentration, showing a sharp enhancement across the optimal doping. These properties (material and doping dependence of the coupling energy) demonstrate the significant correlation among the mode coupling, the energy gap close to the node, and the strong electron correlation. Our results suggest forward scattering arising from the interplay between the electrons and in-plane polarized acoustic phonon branch as the origin of the low-energy renormalization.
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Affiliation(s)
- Takeshi Kondo
- ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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18
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Kang L, Luo S, Huang H, Zheng T, Lin ZS, Chen CT. Ab initio studies on the optical effects in the deep ultraviolet nonlinear optical crystals of the KBe2BO3F2 family. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:335503. [PMID: 22813626 DOI: 10.1088/0953-8984/24/33/335503] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Electronic structures of the deep ultraviolet nonlinear optical crystals of the KBe(2)BO(3)F(2) (KBBF) family, including KBBF, RbBe(2)BO(3)F(2) and CsBe(2)BO(3)F(2), have been investigated based on a plane-wave pseudopotential method. Their linear and nonlinear optical coefficients are also calculated, and are in good agreement with the experimental results. A real-space atom-cutting method is adopted to analyze the respective contributions of the alkali metal cations and anionic groups to optical response. The results show that the contributions of anionic groups to the nonlinear optical anisotropic responses are dominant, but the influence of the A-site alkali metal cations becomes slightly more pronounced with the increase of their radius. Moreover, the birefringence difference among these crystals strongly depends on the volume effect, i.e., the spatial density of the (BO(3))(3-) anionic groups.
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Affiliation(s)
- Lei Kang
- Beijing Center for Crystal R&D, Key Lab of Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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19
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Johnston S, Vishik IM, Lee WS, Schmitt F, Uchida S, Fujita K, Ishida S, Nagaosa N, Shen ZX, Devereaux TP. Evidence for the importance of extended Coulomb interactions and forward scattering in cuprate superconductors. PHYSICAL REVIEW LETTERS 2012; 108:166404. [PMID: 22680740 DOI: 10.1103/physrevlett.108.166404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 12/13/2011] [Indexed: 06/01/2023]
Abstract
The prevalent view of the high-temperature superconducting cuprates is that their essential low-energy physics is captured by local Coulomb interactions. However, this view been challenged recently by studies indicating the importance of longer-range components. Motivated by this, we demonstrate the importance of these components by examining the electron-phonon (e-ph) interaction with acoustic phonons in connection with the recently discovered renormalization in the near-nodal low-energy (~8-15 meV) dispersion of Bi(2)Sr(2)CaCu(2)O(8+δ). By studying its nontrivial momentum and doping dependence we conclude a predominance of forward scattering arising from the direct interplay between the e-ph and extended Coulomb interactions. Our results thus demonstrate how the low-energy renormalization can provide a pathway to new insights into how these interactions interplay with one another and influence pairing and dynamics in the cuprates.
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Affiliation(s)
- S Johnston
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, California 94305, USA
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20
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Gweon GH, Shastry BS, Gu GD. Extremely correlated Fermi-liquid description of normal-state ARPES in cuprates. PHYSICAL REVIEW LETTERS 2011; 107:056404. [PMID: 21867084 DOI: 10.1103/physrevlett.107.056404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Indexed: 05/31/2023]
Abstract
The normal-state single particle spectral function of the high temperature superconducting cuprates, measured by the angle-resolved photoelectron spectroscopy (ARPES), has been considered both anomalous and crucial to understand. Here, we report an unprecedented success of the new extremely correlated Fermi liquid theory by one of us [B. S. Shastry, Phys. Rev. Lett. 107, 056403 (2011)] to describe both laser and conventional synchrotron ARPES data (nodal cut at optimal doping) on Bi(2)Sr(2)CaCu(2)O(8+δ) and synchrotron data on La(1.85)Sr(0.15)CuO(4). It fits all data sets with the same physical parameter values, satisfies the particle sum rule and successfully addresses two widely discussed kink anomalies in the dispersion.
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Affiliation(s)
- G-H Gweon
- Physics Department, University of California, Santa Cruz, California 95064, USA.
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21
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Anzai H, Ino A, Kamo T, Fujita T, Arita M, Namatame H, Taniguchi M, Fujimori A, Shen ZX, Ishikado M, Uchida S. Energy-dependent enhancement of the electron-coupling spectrum of the underdoped Bi2Sr2CaCu2O(8+δ) superconductor. PHYSICAL REVIEW LETTERS 2010; 105:227002. [PMID: 21231415 DOI: 10.1103/physrevlett.105.227002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Indexed: 05/30/2023]
Abstract
We have determined the electron-coupling spectrum of superconducting Bi2Sr2CaCu2O(8+δ) from high-resolution angle-resolved photoemission spectra by two deconvolution-free robust methods. As hole concentration decreases, the coupling spectral weight at low energies ≲15 meV shows a twofold and nearly band-independent enhancement, while that around ∼65 meV increases moderately, and that in ≳130 meV decreases leading to a crossover of dominant coupling excitation between them. Our results suggest the competition among multiple screening effects, and provide important clues to the source of sufficiently strong low-energy coupling, λ(LE)≈1, in an underdoped system.
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Affiliation(s)
- H Anzai
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
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22
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Plumb NC, Reber TJ, Koralek JD, Sun Z, Douglas JF, Aiura Y, Oka K, Eisaki H, Dessau DS. Low-energy (<10 meV) feature in the nodal electron self-energy and strong temperature dependence of the Fermi velocity in Bi{2}Sr{2}CaCu{2}O{8+δ}. PHYSICAL REVIEW LETTERS 2010; 105:046402. [PMID: 20867869 DOI: 10.1103/physrevlett.105.046402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Indexed: 05/29/2023]
Abstract
Using low photon energy angle-resolved photoemission, we study the low-energy dispersion along the nodal (π,π) direction in Bi{2}Sr{2}CaCu{2}O{8+δ} as a function of temperature. Less than 10 meV below the Fermi energy, the high-resolution data reveal a novel "kinklike" feature in the electron self-energy that is distinct from the larger well-known kink roughly 70 meV below E{F}. This new kink is strongest below the superconducting critical temperature and weakens substantially at higher temperatures. A corollary of this finding is that the Fermi velocity v{F}, as measured in this low-energy range, varies rapidly with temperature-increasing by almost 30% from 70 to 110 K. The behavior of v{F}(T) appears to shift as a function of doping, suggesting a departure from simple "universality" in the nodal Fermi velocity of cuprates.
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Affiliation(s)
- N C Plumb
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA.
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23
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Vishik IM, Lee WS, Schmitt F, Moritz B, Sasagawa T, Uchida S, Fujita K, Ishida S, Zhang C, Devereaux TP, Shen ZX. Doping-dependent nodal fermi velocity of the high-temperature superconductor Bi2Sr2CaCu2O(8+δ) revealed using high-resolution angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2010; 104:207002. [PMID: 20867053 DOI: 10.1103/physrevlett.104.207002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Indexed: 05/29/2023]
Abstract
The improved resolution of laser-based angle-resolved photoemission spectroscopy (ARPES) allows reliable access to fine structures in the spectrum. We present a systematic, doping-dependent study of a recently discovered low-energy kink in the nodal dispersion of Bi2Sr2CaCu2O(8+δ) (Bi-2212), which demonstrates the ubiquity and robustness of this kink in underdoped Bi-2212. The renormalization of the nodal velocity due to this kink becomes stronger with underdoping, revealing that the nodal Fermi velocity is nonuniversal, in contrast with assumed phenomenology. This is used together with laser ARPES measurements of the gap velocity (v2) to resolve discrepancies with thermal conductivity measurements.
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Affiliation(s)
- I M Vishik
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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