P.N. First, R.A. Dragoset, et al.
Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
We have simultaneously measured the surface topography and the tunneling current-voltage (I-V) characteristics of thin films of NbN as a function of lateral position using a low-temperature scanning tunneling microscope. We have imaged the superconducting energy gap by fitting the I-V's with an energy gap for each spatial position. Such images showed significant variation of the gap, including areas with reduced gap when a magnetic field (up to 6 T) was applied. The features in the gap image were often correlated with features in the surface topographic images.
P.N. First, R.A. Dragoset, et al.
Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
K. Hasselbach, J.R. Kirtley, et al.
Physical Review B
J.R. Kirtley, K.A. Moler, et al.
Journal of Physics Condensed Matter
A. Hartstein, J.R. Kirtley, et al.
Physical Review Letters