Weak antilocalization and electron-electron interaction effects in Cu-doped Bi2Se3 films

We investigate the low-temperature transport properties in CuxBi2-xSe3 films prepared by a hot-wall-epitaxy growth of Bi2Se3 layers on Cu-deposited substrates. We observe a positive magnetoresistance due to the weak antilocalization effect and a classical magnetoresistance that exhibits a power-law dependence on the magnetic field. The resistance increases logarithmically with lowering temperature regardless of the strength of the magnetic field. The electron-electron interaction effect is thus evidenced to be strong. While the magnitude of the weak antilocalization effect is in reasonable agreement with theory, the correction to the conductivity due to the electron-electron interaction effect is unaccountably larger than the theoretical prediction. The discrepancy may indicate that the contribution from the bulk state is as large as that from the surface states, at least, for the interaction effect.