AVS 57th International Symposium & Exhibition
    In Situ Microscopy and Spectroscopy Topical Conference Wednesday Sessions
       Session IS+AS+NS+MI-WeM

Paper IS+AS+NS+MI-WeM1
Low-dimensional Superconductivity of Pb Nanostructures

Wednesday, October 20, 2010, 8:00 am, Room Acoma

Session: In Situ Microscopy/Spectroscopy – In Situ Nanoscale Processes
Presenter: J. Kim, The University of Texas at Austin
Authors: J. Kim, The University of Texas at Austin
H. Nam, The University of Texas at Austin
G.A. Fiete, The University of Texas at Austin
C.K. Shih, The University of Texas at Austin
Correspondent: Click to Email
The influence of low-dimensional geometries on superconductivity is an important issue to study because in low dimensions it is key to understanding coherence and robustness of the superconducting state in quantum-mechanically confined geometries. The lateral size dependence of superconductivity on 2 dimensional Pb islands is studied by using in-situ low temperature Scanning Tunneling Microscopy/Spectroscopy (STM/S). The superconducting transition temperature (Tc) of each island is obtained by fitting the STS data with a BCS-like density of states. It is found that superconductivity shows a clear dependence on the Pb island lateral size even when it is larger than the bulk coherence length (~80nm), and it is also found that Tc drops very quickly below a certain lateral size. In addition, an intriguing lateral proximity effect is observed at the interface of different local superconducting regions of Pb islands. Current imaging tunneling spectroscopy (CITS) is used to visualize this proximity effect in real space.