What happens when a perfect topological insulator (no bulk band at E_F) is in proximity with a s-wave superconductor? The system can become a Josephson junction with superconducting topological surface state. In this work, our group, in collaboration with Tai C. Chiang's group (UIUC), demonstrated the essential role of Josephson coupling for long-range pairing in the spin-helical Dirac Fermions of topological structures. The paper was published in Nano Letters 25, 16387 (Nov. 8, 2025).