Abstract
Structural and transport properties of thin Nb layers in Si/Nb/Si trilayers with Nb layer thickness from 1.1 nm to 50 nm have been studied. With decreasing thickness, the structure of the Nb layer changes from polycrystalline to amorphous at nm, while the superconducting temperature monotonically decreases. The Hall coefficient varies with systematically but changes sign into negative in ultrathin films with nm. The influence of boundary scattering on the relaxation rate of carriers, and band broadening in the amorphous films, may contribute to this effect.
- Received 22 July 2014
- Revised 11 August 2014
DOI:https://doi.org/10.1103/PhysRevB.90.060505
©2014 American Physical Society