Determination of the density of states in high-Tc thin films using FET-type microstructures
Department of Theoretical Physics, Faculty of Physics, University of Sofia St. Kliment Ohridski, 5 J. Bourchier Boulevard, 1164 Sofia, Bulgaria
Revised: 2 October 2006
Published online: 24 January 2007
A simple electronic experiment using a field-effect-transistor–type microstructure is suggested. The thin superconductor layer forms the source-drain channel of a layered structure across which an AC current is applied. It is found necessary to measure the second harmonic of the source-gate voltage, and the third harmonic of the source-drain voltage; these electronic measurements then give the logarithmic derivative of the density of states, which is an important consideration when fitting parameters of the band structure.
PACS: 74.78.-w – Superconducting films and low-dimensional structures / 71.20.-b – Electron density of states and band structure of crystalline solids / 74.78.Bz – High-Tc films / 73.50.Lw – Thermoelectric effects
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007