Abstract
The electronic structure across the metal-insulator (MI) transition of electron-doped epitaxial films () grown on substrates was studied by means of thermopower () measurements. Significant increase of values accompanied by MI transition was observed, and the transition temperatures of () decreased with in a good linear relation with MI transition temperatures. values of films at were constant at low values of independently of , which reflects a metallic electronic structure, whereas those at almost linearly decreased with logarithmic W concentrations. The gradient of agrees well with , suggesting that films have insulating electronic structures with a parabolic density of state around the conduction band bottom.
- Received 16 June 2014
- Revised 30 September 2014
DOI:https://doi.org/10.1103/PhysRevB.90.161105
©2014 American Physical Society