Characteristics of charging effect in one-dimensional array of Bi ₂Sr₂CaCu₂O_8+δ intrinsic Josephson junctions

For the observation of the charging effect on a Josephson junction, the charging energy (E_c) must be much larger than the Josephson coupling energy (E_J) and thermal energy (k_BT). We investigated the properties of submicron-sized Bi₂Sr₂CaCu₂O _8+δ intrinsic Josephson junctions (IJJs) at low temperature. The current-voltage curve of IJJs with a junction area of 0.06 μm ² showed a much higher resistance state near the zero bias voltage regions when the measurement temperature decreased to 72.6mK. The ratios of E_c/E_J and Eć/k_BT were 7.04 and 5.78, respectively, which indicates that the charging effect is dominant. In addition, a characteristic voltage structure due to the charging effect in one-dimensional junction array, which is composed of the offset voltage and the threshold voltage of the junction, was observed.