Fermi-edge singularity in resonant tunneling

A. K. Geim; P. C. Main; N. La Scala, Jr; L. Eaves; T. J. Foster; P. H. Beton; J. W. Sakai; F. W. Sheard; M. Henini; G. Hill; M. A. Pate

doi:10.1103/PhysRevLett.72.2061

Fermi-edge singularity in resonant tunneling

A. K. Geim, P. C. Main, N. La Scala, Jr., L. Eaves, T. J. Foster, P. H. Beton, J. W. Sakai, F. W. Sheard, M. Henini, G. Hill, and M. A. Pate

Phys. Rev. Lett. 72, 2061 – Published 28 March 1994

Abstract

We have observed a Fermi-edge singularity in the tunneling current between a two-dimensional electron gas (2DEG) and a zero-dimensional localized state. A sharp peak in the tunnel current is observed when the energy of the localized state matches the Fermi energy of the 2DEG. The peak grows and becomes sharper as the temperature is decreased to our lowest temperature of 70 mK. We attribute the singularity to the Coulomb interaction between the tunneling electron on the localized site and the Fermi sea.