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TT: Tiefe Temperaturen

TT 6: Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter I

TT 6.4: Vortrag

Montag, 11. März 2002, 16:45–17:00, H19

Nonmonotonic d_x²−y² Superconducting Order Parameter in Nd_2−xCe_xCuO₄ — •Andreas Koitzsch^1,2, G. Blumberg², A. Gozar², B.S. Dennis², C.A. Kendziora³, P. Fournier⁴, and R.L. Greene⁴ — ¹Institute for Solid State and Materials Research Dresden, P.O.Box 270016, D-01171 Dresden, Germany — ²Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974 — ³United States Naval Research Laboratory, Code 6333, Washington, D.C. 20375 — ⁴Center for Superconductivity Research an Department of Physics, University of Maryland, Collage Park, MD 20742

Electronic Raman scattering of the electron doped superconductor Nd_2−xCe_xCuO₄ (x=0.15, T_c=22 K) has revealed a nonmonotonic d_x²−y² superconducting order parameter. It has a maximum gap of 4.4 k_BT_c at the Fermi surface intersection with the antiferromagnetic Brioullin zone (the No-dqhot spotsNo-dq) and a smaller gap of 3.3k_BT_c at the Brioullin zone boundary. The gap enhancement in the viccinity of the hot spots emphasizes the role of antiferromagnetic fluctuations for the origin of superconductivity in the cuprates.