Josephson installed a thin insulator between superconductors and discovered tunneling through which current flows. Tunneling occurred between the superconductors(55). Likewise, if electrons are moved by tunneling between SQWs, the resistance will naturally be zero. Tunneling between SQWs is likely to be possible, as SQWs are expected to be formed at 3.7 ~ 6.5 intervals in LK-99. According to Kims paper(52), he used 1250 K Debye temperature for his calculation of room-temperature superconductor, which is mentioned for hydride in 1968 by Ashcroft(56). Even in that case, he argued that the electron-electron interaction contributes to the higher temperature superconductivity than the electron-phonon interaction. In LK-99 system, the applied current seems to be transported through the correlated SQWs of the cylindrical column via the tunneling process and coherently transported in 3-dimension with all SQWs together. The additional 12

LK-99 will be an attractive substance for many researchers that can solve various confusing puzzles such as the pairing process and coexistence with magnetism, etc., related to superconductivity. Consequently, why does LK-99 exhibit superconductivity at room temperature and ambient pressure? This is because the stress generated by the Cu2+ replacement of Pb(2)2+ ion was not relieved due to the structural uniqueness of LK-99 and at the same time was appropriately transferred to the interface of the cylindrical column. In other words, the Pb(1) atoms in the cylindrical column interface of LK-99 occupy a structurally limited space. These atoms are entirely

Therefore, SQWs can be generated in the interface by an appropriate amount of distortion(57) at room temperature and ambient pressure without a relaxation. From this point of view, the stress due to volume contraction by temperature and pressure is relieved and disappeared in CuOand Fe-based superconductor systems because the relaxation process cannot be limited due to the structural freedom. Therefore, they need an appropriate temperature or pressure to limit the structural freedom and to achieve the SQW generation. The LK-99 is a very useful material for the study of superconductivity puzzles at room temperature. All evidence and explanation lead that LK-99 is the first room-temperature and ambient-pressure superconductor. The LK-99 has many possibilities for various applications such as magnet, motor, cable, levitation train, power cable, qubit for a quantum computer, THz

Antennas, etc. We believe that our new development will be a brand-new historical event that opens a new era for humankind. 13 References and Notes 1. H. K. Onnes, Further experiments with liquid helium D On the change of the electrical resistance of pure metals at very low temperatures, etc V The disappearance of the resistance of mercury. P K Akad Wet-Amsterd 14, 113-115 (1911). 2. S. Guenon et al., Search for New Superconductors: an Electro-Magnetic Phase Transition in an Iron Meteorite Inclusion at 117 K. J Supercond Nov Magn 30, 297-304 (2017). 3. H. Hosono et al., Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides. Sci Technol Adv Mat 16, 033503 (2015). 4.