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Local and global effects of quantum impurities on the quasi-particle tunneling spectra of p-type and n-type cuprate superconductors

Yeh, N.-C. and Chen, C.-T. and Vasquez, R. P. and Jung, C. U. and Kim, J. Y. and Park, M. S. and Kim, H. J. and Lee, S. I. and Yoshida, K. and Tajima, S. (2002) Local and global effects of quantum impurities on the quasi-particle tunneling spectra of p-type and n-type cuprate superconductors. In: Superconducting and Related Oxides: Physics and Nanoengineering V. Proceedings of SPIE. No.4811. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, pp. 182-194. ISBN 9780819445797.

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We report scanning tunneling spectroscopic studies of the effects of quantum impurities on cuprate superconductors. The samples include p-type YBa_2Cu_3O_(7-δ) single crystals with spinless impurities of Zn^(2+) and Mg^(2+) ((Zn,Mg)-YBCO) and n-type infinite-layer system Sr_(0.9)La)(0.1)CuO_2 with 1% magnetic Ni^(2+)- or 1% non-magnetic Zn^(2+)-impurities that substitute the Cu^(2+) in the CuO)2 plane. The local effects of spinless impurities on the quasiparticles spectra of (Zn,Mg)-YBCO are analogous to those of Zn-substituted Bi_2Sr_2CaCu_2O_(8+x), and the global effect is manifested by the suppression of the pairing potential Δd and of the spin excitation energy. In contrast, spectroscopic studies of Sr_(0.9)La_(0.1)CuO)2 reveal momentum-independent spectra and superconducting gap Δ, with (2Δ/k_BT_c) ~ 7 for T_c = 43 K and no pseudogap above T_c. The global response of Sr_(0.9)La_(0.1)CuO_2 to quantum impurities is similar to that of s-wave superconductors, being insensitive to small concentrations of spinless impurities (Zn) while showing rapid degradation in T_c with increasing magnetic impurities (Ni). Moreover, the spectra of the Ni-substituted Sr_(0.9)La_(0.1)CuO_2 reveal strong electron-hole asymmetry and long-range impurity effects, in contrast to the localized impurity effects in the p-type cuprates, and the introduction of Zn yield no reduction in either Δ or T_c. The physical implications of these findings are discussed.

Item Type:Book Section
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Yeh, N.-C.0000-0002-1826-419X
Additional Information:© 2002 Society of Photo-Optical Instrumentation Engineers (SPIE). The research at Caltech was jointly supported by the NSF Grant No. DMR-0103045 and the Caltech President's Fund. Part of the research was performed by the Center for Space Microelectronics Technology, Jet Propulsion Laboratory, Caltech, and was sponsored by NASA. The work at Pohang University was supported by the Ministry of Science and Technology of Korea through the Creative Research Initiative Program, and the work at SRL/ISTEC in Japan has been partially supported by NEDO.
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Caltech President’s FundUNSPECIFIED
Ministry of Science and Technology (Korea)UNSPECIFIED
New Energy and Industrial Technology Development Organization (NEDO)UNSPECIFIED
Subject Keywords:scanning tunneling spectroscopy (STS), cuprate superconductors, pairing symmetry, quantum impurities, Kondo effect
Series Name:Proceedings of SPIE
Issue or Number:4811
Record Number:CaltechAUTHORS:20181213-143631375
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Official Citation:Nai-Chang Yeh, Ching-Tzu Chen, Richard P. Vasquez, Chang Uk Jung, J. Y. Kim, Min-Seok Park, Heon-Jung Kim, Sung-Ik Lee, K. Yoshida, Setsuko Tajima, "Local and global effects of quantum impurities on the quasi particle tunneling spectra of p-type and n-type cuprate superconductors," Proc. SPIE 4811, Superconducting and Related Oxides: Physics and Nanoengineering V, (7 November 2002); doi: 10.1117/12.452324
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91799
Deposited By: George Porter
Deposited On:19 Dec 2018 22:52
Last Modified:16 Nov 2021 03:44

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