Local tunneling spectra of superconductors

The classical tunneling experiment of Giaever (1960) provided unambiguous proof of the BCS theory of superconductivity. The STM as a local tunneling probe is certainly suitable to probe the local properties of superconductors, such as the local structure of the Abrikosov flux lattice. The work of Hess and co-workers (1989, 1990, 1990a, 1991) is a prominent example. 

Similar to the tunneling junction experiments, the choice of materials is crucial. In the tunneling junction experiment, the existence of an excellent insulator AI2O3 and the ease of growing it on Al surfaces is the key to its 

Subsequent studies revealed, for the first time, the anisotropic structure of the vortex, and the interactions among vortices that give rise to a well-defined, oriented lattice structure aligned with the crystallographic orientations of 2//-NbSe2 (Hess et al, 1990a). For details, see Hess et al. (1991). 

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