Materials with large magneto-resistance (MR) have been of great interest in both fundamental research and device applications. The linear MR (LMR) of single crystalline topological insulator in perpendicular field was attributed to the 2D gapless topological surface states and of quantum origin. Up to date; it still remains unclear if the LMR in topological insulator is due to the unique zero-gap nature of surface states or any physical/electronic inhomogeneity in sample.Here, we report a study of Bi2Te3 films of interconnected nanoplates synthesized by CVD method. The non-saturating LMR was observed in these films with variable granularity or uniformity up to 14T magnetic field, the highest field available in our instrument. Similar to many other topological insulator materials, these granular Bi2Te3 films exhibit a LMReffect which has received much recent attention. Studying samples with different degree of granularity, we find a universal correlation between the magnitude of the LMR and the average mobility of the films over nearly two orders of magnitude change of the average mobility. A close correlation between LMR, average mobility and the sample’s uniformity was revealed over a broad range of parameter space (near two orders of magnitude change in mobility and LMR’s magnitude). The granularity controlled LMR effect here is attributed to the mobility fluctuation induced classical LMR according to the Parish-Little wood theory. Our work on granular films of Bi2Te3nanoplates provides a definite evidence for the relevance of sample’s physical or structural inhomogeneity in the origin of LMR and offers a new route to control the magneto-resistive properties of topological insulator materials.

Fig. 4 SEM image of typical granular Bi₂Te₃ films.

Fig.(left)Magneto-resistance ΔR(B)/R(0) (defined as [R(B)-R(0)]/R(0)) as a function of magnetic field at different temperatures. Inset of right, SEM image of typical sample. (right)The relation of mobility<μ>and ΔR(B=14T)/R(B=0) for different samples with different granularity.