Momentum dependence of superconducting gap, strong-coupling dispersion kink, and tightly bound Cooper pairs in the high- Tc (Sr,Ba) 1-x(K,Na)xFe2As2 superconductors

L. Wray, D. Qian, D. Hsieh, Y. Xia, L. Li, J. G. Checkelsky, A. Pasupathy, K. K. Gomes, C. V. Parker, A. V. Fedorov, G. F. Chen, J. L. Luo, A. Yazdani, N. P. Ong, N. L. Wang, M. Z. Hasan

    Research output: Contribution to journalArticle

    Abstract

    We present a systematic angle-resolved photoemission spectroscopic study of the high- Tc superconductor class (Sr/Ba) 1-x Kx Fe2 As2. By utilizing a photon-energy-modulation contrast and scattering geometry we report the Fermi surface and the momentum dependence of the superconducting gap, Δ (k→). A prominent quasiparticle dispersion kink reflecting strong scattering processes is observed in a binding-energy range of 25-55 meV in the superconducting state, and the coherence length or the extent of the Cooper pair wave function is found to be about 20 Å, which is uncharacteristic of a superconducting phase realized by the BCS-phonon-retardation mechanism. The observed 40±15 meV kink likely reflects contributions from the frustrated spin excitations in a J1 - J2 magnetic background and scattering from the soft phonons. Results taken collectively provide direct clues to the nature of the pairing potential including an internal phase-shift factor in the superconducting order parameter which leads to a Brillouin zone node in a strong-coupling setting.

    Original languageEnglish (US)
    Article number184508
    JournalPhysical Review B - Condensed Matter and Materials Physics
    Volume78
    Issue number18
    DOIs
    StatePublished - Nov 10 2008

    Fingerprint

    Superconducting materials
    Momentum
    Scattering
    momentum
    scattering
    Fermi surface
    Photoemission
    Phonons
    Wave functions
    Binding energy
    Brillouin zones
    Phase shift
    Fermi surfaces
    phonons
    phase shift
    photoelectric emission
    Photons
    binding energy
    Modulation
    wave functions

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Electronic, Optical and Magnetic Materials

    Cite this

    Momentum dependence of superconducting gap, strong-coupling dispersion kink, and tightly bound Cooper pairs in the high- Tc (Sr,Ba) 1-x(K,Na)xFe2As2 superconductors. / Wray, L.; Qian, D.; Hsieh, D.; Xia, Y.; Li, L.; Checkelsky, J. G.; Pasupathy, A.; Gomes, K. K.; Parker, C. V.; Fedorov, A. V.; Chen, G. F.; Luo, J. L.; Yazdani, A.; Ong, N. P.; Wang, N. L.; Hasan, M. Z.

    In: Physical Review B - Condensed Matter and Materials Physics, Vol. 78, No. 18, 184508, 10.11.2008.

    Research output: Contribution to journalArticle

    Wray, L, Qian, D, Hsieh, D, Xia, Y, Li, L, Checkelsky, JG, Pasupathy, A, Gomes, KK, Parker, CV, Fedorov, AV, Chen, GF, Luo, JL, Yazdani, A, Ong, NP, Wang, NL & Hasan, MZ 2008, 'Momentum dependence of superconducting gap, strong-coupling dispersion kink, and tightly bound Cooper pairs in the high- Tc (Sr,Ba) 1-x(K,Na)xFe2As2 superconductors', Physical Review B - Condensed Matter and Materials Physics, vol. 78, no. 18, 184508. https://doi.org/10.1103/PhysRevB.78.184508
    Wray, L. ; Qian, D. ; Hsieh, D. ; Xia, Y. ; Li, L. ; Checkelsky, J. G. ; Pasupathy, A. ; Gomes, K. K. ; Parker, C. V. ; Fedorov, A. V. ; Chen, G. F. ; Luo, J. L. ; Yazdani, A. ; Ong, N. P. ; Wang, N. L. ; Hasan, M. Z. / Momentum dependence of superconducting gap, strong-coupling dispersion kink, and tightly bound Cooper pairs in the high- Tc (Sr,Ba) 1-x(K,Na)xFe2As2 superconductors. In: Physical Review B - Condensed Matter and Materials Physics. 2008 ; Vol. 78, No. 18.
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    abstract = "We present a systematic angle-resolved photoemission spectroscopic study of the high- Tc superconductor class (Sr/Ba) 1-x Kx Fe2 As2. By utilizing a photon-energy-modulation contrast and scattering geometry we report the Fermi surface and the momentum dependence of the superconducting gap, Δ (k→). A prominent quasiparticle dispersion kink reflecting strong scattering processes is observed in a binding-energy range of 25-55 meV in the superconducting state, and the coherence length or the extent of the Cooper pair wave function is found to be about 20 {\AA}, which is uncharacteristic of a superconducting phase realized by the BCS-phonon-retardation mechanism. The observed 40±15 meV kink likely reflects contributions from the frustrated spin excitations in a J1 - J2 magnetic background and scattering from the soft phonons. Results taken collectively provide direct clues to the nature of the pairing potential including an internal phase-shift factor in the superconducting order parameter which leads to a Brillouin zone node in a strong-coupling setting.",
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    AU - Qian, D.

    AU - Hsieh, D.

    AU - Xia, Y.

    AU - Li, L.

    AU - Checkelsky, J. G.

    AU - Pasupathy, A.

    AU - Gomes, K. K.

    AU - Parker, C. V.

    AU - Fedorov, A. V.

    AU - Chen, G. F.

    AU - Luo, J. L.

    AU - Yazdani, A.

    AU - Ong, N. P.

    AU - Wang, N. L.

    AU - Hasan, M. Z.

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    N2 - We present a systematic angle-resolved photoemission spectroscopic study of the high- Tc superconductor class (Sr/Ba) 1-x Kx Fe2 As2. By utilizing a photon-energy-modulation contrast and scattering geometry we report the Fermi surface and the momentum dependence of the superconducting gap, Δ (k→). A prominent quasiparticle dispersion kink reflecting strong scattering processes is observed in a binding-energy range of 25-55 meV in the superconducting state, and the coherence length or the extent of the Cooper pair wave function is found to be about 20 Å, which is uncharacteristic of a superconducting phase realized by the BCS-phonon-retardation mechanism. The observed 40±15 meV kink likely reflects contributions from the frustrated spin excitations in a J1 - J2 magnetic background and scattering from the soft phonons. Results taken collectively provide direct clues to the nature of the pairing potential including an internal phase-shift factor in the superconducting order parameter which leads to a Brillouin zone node in a strong-coupling setting.

    AB - We present a systematic angle-resolved photoemission spectroscopic study of the high- Tc superconductor class (Sr/Ba) 1-x Kx Fe2 As2. By utilizing a photon-energy-modulation contrast and scattering geometry we report the Fermi surface and the momentum dependence of the superconducting gap, Δ (k→). A prominent quasiparticle dispersion kink reflecting strong scattering processes is observed in a binding-energy range of 25-55 meV in the superconducting state, and the coherence length or the extent of the Cooper pair wave function is found to be about 20 Å, which is uncharacteristic of a superconducting phase realized by the BCS-phonon-retardation mechanism. The observed 40±15 meV kink likely reflects contributions from the frustrated spin excitations in a J1 - J2 magnetic background and scattering from the soft phonons. Results taken collectively provide direct clues to the nature of the pairing potential including an internal phase-shift factor in the superconducting order parameter which leads to a Brillouin zone node in a strong-coupling setting.

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