TY - JOUR
T1 - Quantum Vortex Core and Missing Pseudogap in the Multiband BCS-BEC Crossover Superconductor FeSe
AU - Hanaguri, T.
AU - Kasahara, S.
AU - Böker, J.
AU - Eremin, I.
AU - Shibauchi, T.
AU - Matsuda, Y.
N1 - Funding Information:
We thank Y. Kato, K. Machida, and Y. Nagai for valuable comments. This work has been supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (Grants No. 15H02106, No. 15H05852, No. 16H04024, No. 18H01177, and No. 18H05227). J. B. and I. E. were supported by the joint DFG-ANR Project (No. ER463/8-1) and DAAD PPP USA Grant No. N57316180. The work of I. E. was carried out with financial support from the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST MISiS Grant No. K2-294 2017-085.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/2/21
Y1 - 2019/2/21
N2 - FeSe is argued as a superconductor in the Bardeen-Cooper-Schrieffer Bose-Einstein condensation crossover regime where the superconducting gap size and the superconducting transition temperature Tc are comparable to the Fermi energy. In this regime, vortex bound states should be well quantized and the preformed pairs above Tc may yield a pseudogap in the quasiparticle-excitation spectrum. We performed spectroscopic-imaging scanning tunneling microscopy to search for these features. We found Friedel-like oscillations near the vortex, which manifest the quantized levels, whereas the pseudogap was not detected. These apparently conflicting observations may be related to the multiband nature of FeSe.
AB - FeSe is argued as a superconductor in the Bardeen-Cooper-Schrieffer Bose-Einstein condensation crossover regime where the superconducting gap size and the superconducting transition temperature Tc are comparable to the Fermi energy. In this regime, vortex bound states should be well quantized and the preformed pairs above Tc may yield a pseudogap in the quasiparticle-excitation spectrum. We performed spectroscopic-imaging scanning tunneling microscopy to search for these features. We found Friedel-like oscillations near the vortex, which manifest the quantized levels, whereas the pseudogap was not detected. These apparently conflicting observations may be related to the multiband nature of FeSe.
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U2 - 10.1103/PhysRevLett.122.077001
DO - 10.1103/PhysRevLett.122.077001
M3 - Article
C2 - 30848633
AN - SCOPUS:85062036181
SN - 0031-9007
VL - 122
JO - Physical Review Letters
JF - Physical Review Letters
IS - 7
M1 - 077001
ER -