Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 18: Supraleitung: Tunneln, Josephson-Kontakte, SQUIDs

TT 18.4: Vortrag

Mittwoch, 10. März 2004, 15:15–15:30, H20

Doping dependence of pseudogap and superconductivity in electron doped high-temperature-superconductors: results from tunneling spectroscopy — •B. Welter¹, L. Alff¹, Y. Krockenberger¹, M. Naito², and R. Gross¹ — ¹Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner-Str. 8, 85748 Garching, Germany — ²NTT Basic Research Laboratories, Atsugi, Japan

Studying the influence of doping on the characteristics of oxide superconductors is essential to both the understanding of the underlying physics and the development of new applications. Here, we report on tunneling spectroscopy measurements on grain boundary junctions of electron doped high-temperature superconductors La_2−xCe_xCuO₄, Pr_2−xCe_xCuO₄ and Nd_2−xCe_xCuO₄ with different Ce concentrations around optimal doping. We focus on the pronounced depletion in the density of states near E_F observed in the normal state above B_c2 and its evolution with temperature, magnetic field and doping [1]. Considerations concerning the conservation of states rule even indicate a coexistence of this pseudogap regime and the superconducting state.[2]

[1] L. Alff, Y. Krockenberger, B. Welter, M. Schonecke, R. Gross, D. Manske and M. Naito, Nature 422, 698 (2003)

[2] B. Welter, Y. Krockenberger, L. Alff, M. Naito und R. Gross, to appear in Physica C