Research and application progress of high-temperature superconducting Bi₂Sr₂CaCu₂O_{8+<bold><italic>δ</italic></bold>} single crystal devices

The high-temperature superconductor Bi2Sr2CaCu2O8+δ (BSCCO) single crystal devices, with their unique intrinsic Josephson junction array structure, have demonstrated remarkable research value and application potential over the past three decades. In the past five years, the field has achieved breakthrough progress, showing a diversified development trend, with significant results in fabrication technology, terahertz radiation technology, detection technology, and emerging applications, etc. In terms of fabrication technology, the collaborative innovation of two-dimensional material fabrication technology and micro/nano fabrication technology has driven a breakthrough in the fabrication technology of BSCCO single crystal devices. This paper systematically elaborates on the challenges to be addressed, fabrication process flow, core competitive advantages, and application scenarios of each core technology. The successful application of cryogenic dry transfer technology has achieved lossless transfer of atomic-level thickness materials, laying a solid foundation for the preparation of high-quality BSCCO single-crystal devices. The silicon nitride hard mask and room-temperature high-vacuum in-situ evaporation technology have established an electrode preparation process system suitable for multiple scenarios, significantly improving the stability and success rate of sample preparation. The introduction of localized metal deposition technology and focused helium ion beam irradiation technology has achieved precise control of nano-scale lattice structures, providing key technical support for further improving device performance, marking the entry of high-temperature superconducting electronic device fabrication technology into a new stage. In addition, this paper introduces breakthroughs in the application expansion of BSCCO crystal devices in detail. In the field of terahertz radiation technology, performance optimization and technological innovation have shown potential in communication transmitter applications, providing new possibilities for the development of terahertz communication technology. In the field of detection technology, the technological barrier of integrating an intrinsic junction and antenna structure integration has been overcome. Researchers successfully developed a high-temperature superconducting probe microscope system, which provides an innovative solution for chip characterization. It is noteworthy that emerging applications exhibit stronger interdisciplinary characteristics. For example, the infrared superconducting single-photon detector operating at 25 K has broken through the working temperature limitations of traditional low-temperature superconducting detectors, offering a new high-sensitivity solution for national strategic fields such as deep-space communication. At the same time, the rapid development of high-temperature superconducting diodes and the proposal of new quantum bit theoretical models have not only enriched the theoretical framework of high-temperature superconducting electronics but also built a bridge for technological collaborative development with frontier fields such as quantum information and weak signal detection, promoting the deepening of interdisciplinary integration. Finally, this paper discusses future research directions for devices in this material system. The above breakthrough achievements have not only laid a solid foundation for the practical application of high-temperature superconducting electronics in terahertz technology, but also opened up new paths for frontier fields such as deep-space communication, low-power logic circuits, and quantum computing, etc. These technological advancements have not only promoted the expansion of application scenarios such as cross-scale integration and multi-physical field coupling but also demonstrated the broad application prospects and continuous development vitality of high-temperature superconducting electronics in the context of interdisciplinary integration.