Vacuum tunneling of superconducting quasiparticles from atomically sharp scanning tunneling microscope tips
نویسندگان
چکیده
We report on the study of atomically sharp superconducting tips for scanning tunneling microscopy and spectroscopy. The results clearly show vacuum tunneling of superconducting quasiparticles from atomically sharp tips. Observed deviations of the energy gap of the superconducting tip from its bulk value are attributed to the proximity effect. We show that a combination of a superconducting tip and an atomic resolution scanning tunneling microscope provides a means of achieving very high resolution local spectroscopy. We also discuss how this combination paves the way for a number of important applications. © 1998 American Institute of Physics. @S0003-6951~98!04446-5#
منابع مشابه
Theory of a scanning tunneling microscope with a two-protrusion tip.
We consider a scanning tunneling microscope (STM) such that tunneling occurs through two atomically sharp protrusions on its tip. When the two protrusions are separated by at least several atomic spacings, the differential conductance of this STM depends on the electronic transport in the sample between the protrusions. Such two-protrusion tips commonly occur during STM tip preparation. We expl...
متن کاملA 30 mK, 13.5 T scanning tunneling microscope with two independent tips.
We describe the design, construction, and performance of an ultra-low temperature, high-field scanning tunneling microscope (STM) with two independent tips. The STM is mounted on a dilution refrigerator and operates at a base temperature of 30 mK with magnetic fields of up to 13.5 T. We focus on the design of the two-tip STM head, as well as the sample transfer mechanism, which allows in situ t...
متن کاملA THEORY OF VACUUM TUNNELING MICROSCOPY1
A theory for tunneling between a real surface and a model probe tip, applicable to the "scanning tunneling microscope" is presented. The tunneling current is found to be proportional to the local density of states of the surface, at the position of the tip. It can be shown that the tunneling conductance has exponential dependence on the distance of the nearest approach to the surface
متن کاملHigh resolution STM imaging with oriented single crystalline tips
Precise knowledge of the atomic and electronic structure of scanning tunneling microscopy (STM) tips is crucial for correct interpretation of atomically resolved STM data and improvement of spatial resolution. Here we demonstrate that tungsten probes with controllable electronic structure can be fabricated using oriented single crystalline tips. High quality of the [001]-oriented W tips sharpen...
متن کاملScanning tunneling microscope studies of the superconductor proximity effect
Scanning tunneling microscopy and spectroscopy are employed in studies of the proximity effect between normal metals and superconductors. The experimental configuration is unique, in that the tunneling current flows in parallel to the interfaces between different materials. The samples are superconducting wires consisting of ordered arrays of submicron diameter normal-metal filaments, either Cu...
متن کامل