Superconducting Scanning Tunneling Microscope -- Josephson effect and High-T$_{C}$ superconducting cuprate

We have developed and characterized superconducting scanning tunneling microscope (STM) tips that consist of Pb coated Pt/Ir wires. We have observed the thermally fluctuated Josephson effects between a conventional superconductor and this superconducting STM. STM-based Josephson junctions formed between the superconducting-STM tip and superconducting samples can be a powerful tool to detect both superconducting quasiparticles and the phase of the superconducting condensate via the Josephson effect on a length scale of nanometers. This technique is especially powerful when we study spatially inhomogeneous electronic systems such as High-T$_{C}$ superconducting cuprates. In this talk we present data of the STM Josephson junctions formed between S-STM tips and both Pb/Ag films and NbSe$_{2}$ single crystals. The former experiments give us the effective noise temperature T$_{n}$ and the impedance of the environment around the junction, Z$_{env}$. The latter is a precursor to the Pb/I/HT$_{C}$ cuprate Josephson junctions. We have derived the I$_{C}$R$_{N}$ product of NbSe$_{2}$ junctions using T$_{n}$ and Z$_{env}$ obtained as described above. Preliminary results of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$ single crystals by S-STM tips are also discussed. This work is supported by DOE Grant No. FDDE-FG02-05ER46194.