Direct observation of self-heating in intrinsic Josephson junction array with a nanoelectrode in the middle

Modifying the double-sided fabrication method we invented a few years ago, a new type of Bi2Sr2CaCu2O8 intrinsic Josephson junction (IJJs) array is explored in which, in addition to the indispensable top and bottom electrodes, there is an electrode only 100 nm thick fabricated in the middle of the array. This electrode provides easy access to the inside of the IJJs, enabling us to understand the device physics better than was possible before. As the first application of such a new device, we have clearly shown how “hot” a junction stack can be under various bias conditions.