Linear magnetoresistance in Cr-doped Bi2Se3 thin film

This paper reports the magnetotransport property of a Cr-doped Bi2Se3 thin film. A linear magnetoresistance (MR) is observed in a high field region, while the weak antilocalization effect appears up near zero magnetic fields below 15 K, and it is transformed into a positive parabolic MR at high temperatures. It is found that the slope of the observed linear MR is proportional to the Hall mobility. Meanwhile, a crossover field from the parabolic MR to the linear MR is proportional to the inverse Hall mobility. These indicate that the observed linear MR can be explained by the classical mechanism. Most importantly, we find that the observed linear MR is suppressed with increasing time when the film is sealed in vacuum after growth. This indicates that the observed linear MR does not originate from a two-dimensional electron gas formed on the film surface. It is found that the observed linear MR is likely to arise from the bulk state.