Energy gap suppression and excess current in Tl₂Ba₂CaCu₂O₈intrinsic Josephson junctions

Abstract

Intrinsic Josephson junctions in misaligned Tl2Ba2CaCu2O8 thin film were fabricated on LaAlO3 substrate. The temperature dependence of the critical current is investigated around liquid nitrogen temperature. In the current voltage characteristic, large voltage jump and lack of resistive branch are observed, which shows good consistency with the intrinsic Josephson junctions. By analyzing the large gap voltage in the curve, great suppression of the energy gap is found. Through discussing the temperature dependence of the gap voltage in liquid nitrogen temperature, it is shown that this phenomenon can be caused by the non-equilibrium quasiparticle injection. The temperature influence on the excess current also confirms the non-equilibrium effect.

Transport properties of Tl2Ba2CaCu2O8 microbridges on a low-angle step substrate

“…Tl-2212 has an operating temperature over 100 K, [15] which is much higher than that of BSCCO and YBa 2 Cu 3 O 7−δ (YBCO). Intrinsic Josephson effects and other superconducting properties of Tl-2212 IJJs were mostly investigated on misaligned substrate, [16][17][18][19][20][21][22][23][24][25][26][27][28] in which films were grown epitaxially on the substrate with the same misalignment angle. In this structure, the copper oxide planes of Tl-based films create a misaligned angle with respect to the substrate surface, the superconducting current can then flow through the inter-plane along the c-axis of the sample films according to the experimental design.…”

0– π transition induced by the barrier strength in spin superconductor Josephson junctions

“…[18][19][20][21][22][23] The charge supercurrent across the junction is mediated by the Andreev bound states formed by the electrons and holes inside the normal segment of the junction. [24][25][26][27][28][29][30][31] As an analogy of the conventional Josephson junction, the SSC Josephson junction can be achieved by a weak link between two SSCs. There are both the spin-conserved and the spinflip reflections at the normal-metal/SSC interface, [3] which are the counterparts of the normal reflection and the Andreev reflection at the normal-metal/superconductor interface, respectively.…”