This paper deals with measurements of conductivity modulation in metals by an electric field. The measurements have been performed using a new technique, which permits reaching an accuracy sensibly higher than that obtained in experiments already published.

Measurements on Au, Sb, and Bi films have been carried out at different temperatures between about -20 and +80°C. The existence of localized and conducting "surface states" at the metal/dielectric interface seems to be experimentally confirmed.

• Received 17 February 1959

DOI:https://doi.org/10.1103/PhysRev.115.330