Coexistence of Weak and Strong Coupling Mechanism, in an Iron-Based Superconductor FeSe 0.5 Te 0.5: Possible Signature of BCS-BEC Crossover

S. Kunwar; R. M. Hamad; Kh A. Ziq

doi:10.1007/s10948-017-4103-8

Coexistence of Weak and Strong Coupling Mechanism, in an Iron-Based Superconductor FeSe _0.5 Te _0.5: Possible Signature of BCS-BEC Crossover

S. Kunwar^*
, R. M. Hamad
, Kh A. Ziq

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

In this work, we present the scanning tunneling microscopy/spectroscopy (STM/STS) studies of an iron-based superconductor, FeSe_0.5Te_0.5. We obtained differential conductance (dI/dV) spectra and extracted the value of the superconducting order parameter Δ using extended Bardeen Cooper Schieffer (BCS) phenomenology for anisotropic s-wave pairing. We observed widespread values of Δ from ∼0.6 to ∼4.5 meV, with distinct two peaks in the histogram around 1 and 3 meV. The corresponding values of 2Δ/k_BT_c for the peaks are ∼1.5 and ∼5.0, respectively, indicating coexistence of weak and strong coupling mechanism. We also found two different coupling mechanisms through Δ to Fermi energy ratio (Δ/E_f) of the material; which infers to the possible composite superconductivity in the realm of BCS-Bose Einstein Condensate (BEC) crossover.

Original language	English
Pages (from-to)	3183-3188
Number of pages	6
Journal	Journal of Superconductivity and Novel Magnetism
Volume	30
Issue number	11
DOIs	https://doi.org/10.1007/s10948-017-4103-8
State	Published - 1 Nov 2017

Bibliographical note

Publisher Copyright:
© 2017, Springer Science+Business Media New York.

Keywords

BCS-BEC crossover in high- T superconductor
Coupling mechanism in iron-based superconductor
High- T superconductor
Iron-based superconductor

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

Access to Document

10.1007/s10948-017-4103-8

Cite this

@article{051bceace5794bfb9d41856669a74f16,

title = "Coexistence of Weak and Strong Coupling Mechanism, in an Iron-Based Superconductor FeSe 0.5 Te 0.5: Possible Signature of BCS-BEC Crossover",

abstract = "In this work, we present the scanning tunneling microscopy/spectroscopy (STM/STS) studies of an iron-based superconductor, FeSe0.5Te0.5. We obtained differential conductance (dI/dV) spectra and extracted the value of the superconducting order parameter Δ using extended Bardeen Cooper Schieffer (BCS) phenomenology for anisotropic s-wave pairing. We observed widespread values of Δ from ∼0.6 to ∼4.5 meV, with distinct two peaks in the histogram around 1 and 3 meV. The corresponding values of 2Δ/kBTc for the peaks are ∼1.5 and ∼5.0, respectively, indicating coexistence of weak and strong coupling mechanism. We also found two different coupling mechanisms through Δ to Fermi energy ratio (Δ/Ef) of the material; which infers to the possible composite superconductivity in the realm of BCS-Bose Einstein Condensate (BEC) crossover.",

keywords = "BCS-BEC crossover in high- T superconductor, Coupling mechanism in iron-based superconductor, High- T superconductor, Iron-based superconductor",

author = "S. Kunwar and Hamad, \{R. M.\} and Ziq, \{Kh A.\}",

note = "Publisher Copyright: {\textcopyright} 2017, Springer Science+Business Media New York.",

year = "2017",

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T1 - Coexistence of Weak and Strong Coupling Mechanism, in an Iron-Based Superconductor FeSe 0.5 Te 0.5

T2 - Possible Signature of BCS-BEC Crossover

AU - Kunwar, S.

AU - Hamad, R. M.

AU - Ziq, Kh A.

PY - 2017/11/1

Y1 - 2017/11/1

N2 - In this work, we present the scanning tunneling microscopy/spectroscopy (STM/STS) studies of an iron-based superconductor, FeSe0.5Te0.5. We obtained differential conductance (dI/dV) spectra and extracted the value of the superconducting order parameter Δ using extended Bardeen Cooper Schieffer (BCS) phenomenology for anisotropic s-wave pairing. We observed widespread values of Δ from ∼0.6 to ∼4.5 meV, with distinct two peaks in the histogram around 1 and 3 meV. The corresponding values of 2Δ/kBTc for the peaks are ∼1.5 and ∼5.0, respectively, indicating coexistence of weak and strong coupling mechanism. We also found two different coupling mechanisms through Δ to Fermi energy ratio (Δ/Ef) of the material; which infers to the possible composite superconductivity in the realm of BCS-Bose Einstein Condensate (BEC) crossover.

AB - In this work, we present the scanning tunneling microscopy/spectroscopy (STM/STS) studies of an iron-based superconductor, FeSe0.5Te0.5. We obtained differential conductance (dI/dV) spectra and extracted the value of the superconducting order parameter Δ using extended Bardeen Cooper Schieffer (BCS) phenomenology for anisotropic s-wave pairing. We observed widespread values of Δ from ∼0.6 to ∼4.5 meV, with distinct two peaks in the histogram around 1 and 3 meV. The corresponding values of 2Δ/kBTc for the peaks are ∼1.5 and ∼5.0, respectively, indicating coexistence of weak and strong coupling mechanism. We also found two different coupling mechanisms through Δ to Fermi energy ratio (Δ/Ef) of the material; which infers to the possible composite superconductivity in the realm of BCS-Bose Einstein Condensate (BEC) crossover.

KW - BCS-BEC crossover in high- T superconductor

KW - Coupling mechanism in iron-based superconductor

KW - High- T superconductor

KW - Iron-based superconductor

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