Energy gap suppression and excess current in Tl₂Ba₂CaCu₂O₈ intrinsic Josephson junctions

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 free 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 showed that this phenomenon can be caused by the nonequilibrium quasiparticle injection. The temperature influence on the excess current also confirms the nonequlibrium effect.