Electron localization and interaction in bismuth thin films

We have studied the conductivity of thin bismuth films (thickness L≈100-200 Å) for temperatures from 1.4 to 4.2 K and magnetic fields up to ∼50 kOe. The low-temperature behavior includes an increase in electrical resistance as temperature is lowered and an anomalous positive magnetoresistance. These features can be quantitatively described in terms of a theory accounting for electron localization and interaction in two-dimensional systems. The experimental data for conductivity in a perpendicular magnetic field are analyzed as suggested by the theory of Altshuler, Aronov, Larkin, and Khmel'nitskii and those for a parallel field by the theory of Altshuler and Aronov. The inelastic electron relaxation time at 1.4-4.2 K was found to vary as T ^-p, where p=1.3-1.5.