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Evidence of s-Wave Subdominant Order Parameter in YBCO from Break Junction Tunneling Spectra

A. I. Akimenko·F. Bobba·F. Giubileo·V. Gudimenko·A. Scarfato·A. M. Cucolo
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Abstract

The tunneling spectra of YBa2Cu3O7 break-junctions have been investigated for the tunneling direction close to the node one. The zero-bias conductance peak (ZBCP) and Josephson current have been studied with temperature and magnetic field. The observed deep splitting of ZBCP which starts at Ts<20-30K is in agreement with the theory for the dx2-y2+-is order parameter [Y. Tanuma, Y. Tanaka, and S. Kashiwaya, Phys. Rev. B 64, 214519 (2001)]. The low (0.04T) magnetic field depresses significantly such splitting. The 1/T temperature dependence of maximum Josephson current goes to saturation at T<Ts also confirming the mixed order parameter formation.

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A. I. Akimenko, F. Bobba, F. Giubileo, V. Gudimenko, A. Scarfato, A. M. Cucolo. 2007-04-24. Evidence of s-Wave Subdominant Order Parameter in YBCO from Break Junction Tunneling Spectra. https://arxiv.org/abs/cond-mat/0606552

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