Anomalous density of states in hybrid normal metal-superconductor bilayers |
| |
Authors: | A K Gupta L Crétinon B Pannetier H Courtois |
| |
Institution: | (1) Department of Physics, Indian Institute of Technology Kanpur, 208 016 Kanpur, India;(2) Centre de Recherches sur les Très Basses Températures, C.N.R.S. associé à l’Université Joseph Fourier, 25 Avenue des Martyrs, 38042 Grenoble, France |
| |
Abstract: | In contact with a superconductor, the Andreev reflection of the electrons locally modifies the N metal electronic properties,
including the local density of states (LDOS). We investigated the LDOS in superconductor-normal metal (Nb-Au) bilayers using
a very low temperature (60 mK) STM on the normal metal side. High resolution tunneling spectra measured on the Au surface
show a clear proximity effect with an energy gap of reduced amplitude compared to the bulk Nb gap. The dependence of this
mini-gap width with the normal metal thickness is discussed in terms of the Thouless energy. Within the mini-gap, the density
of states does not reach zero and shows clear sub-gap features. We compare the experimental spectra with the well-established
quasi-classical theory. |
| |
Keywords: | Proximity effect density of states Andreev reflection |
本文献已被 SpringerLink 等数据库收录! |
|