TY - JOUR
T1 - Direct observation of superconducting gap in YB6 by ultrahigh-resolution photoemission spectroscopy
AU - Souma, S.
AU - Komoda, H.
AU - Iida, Y.
AU - Sato, T.
AU - Takahashi, T.
AU - Kunii, S.
N1 - Funding Information:
This work was supported by a grant from the MEXT of Japan. S. S. thanks the Sasakawa Scientific Research Grant from the Japan Society and the Japan Science Promotion of Science for financial support.
PY - 2005/6
Y1 - 2005/6
N2 - We have performed ultrahigh-resolution photoemission spectroscopy (PES) on superconducting hexaboride YB6 (Tc=7.1 K) to investigate the electronic structure in the vicinity of the Fermi level (EF). We have succeeded in directly observing the superconducting gap together with a sharp coherent peak in the superconducting state (5K). From the numerical simulation of the PES spectra by using isotropic Dynes function, we have estimated the size of the superconducting gap to be 0.9 meV, which corresponds to 2Δ (0)/kBTc=3.8. We found a dip structure around 10 meV with respect to EF in the PES spectrum in the superconducting state. This structure is attributed to the strong coupling feature of electrons with the 10 meV acoustic phonon. These results indicate that YB6 is categorized into phonon-mediated BCS superconductor in the strong or intermediate coupling regime.
AB - We have performed ultrahigh-resolution photoemission spectroscopy (PES) on superconducting hexaboride YB6 (Tc=7.1 K) to investigate the electronic structure in the vicinity of the Fermi level (EF). We have succeeded in directly observing the superconducting gap together with a sharp coherent peak in the superconducting state (5K). From the numerical simulation of the PES spectra by using isotropic Dynes function, we have estimated the size of the superconducting gap to be 0.9 meV, which corresponds to 2Δ (0)/kBTc=3.8. We found a dip structure around 10 meV with respect to EF in the PES spectrum in the superconducting state. This structure is attributed to the strong coupling feature of electrons with the 10 meV acoustic phonon. These results indicate that YB6 is categorized into phonon-mediated BCS superconductor in the strong or intermediate coupling regime.
KW - Photoemission spectroscopy
KW - Superconductivity
KW - YB
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U2 - 10.1016/j.elspec.2005.01.125
DO - 10.1016/j.elspec.2005.01.125
M3 - Article
AN - SCOPUS:17544371496
VL - 144-147
SP - 503
EP - 506
JO - Journal of Electron Spectroscopy and Related Phenomena
JF - Journal of Electron Spectroscopy and Related Phenomena
SN - 0368-2048
ER -