Granularity controlled nonsaturating linear magnetoresistance in topological insulator Bi2Te3 films

We report on the magnetotransport properties of chemical vapor deposition grown films of interconnected Bi2Te3 nanoplates. Similar to many other topological insulator (TI) materials, these granular Bi2Te3 films exhibit a linear magnetoresistance (LMR) effect 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 (⟨μ⟩) of the films over nearly 2 orders of magnitude change of ⟨μ⟩. The granularity controlled LMR effect here is attributed to the mobility fluctuation induced classical LMR according to the Parish-Littlewood theory. These findings have implications to both the fundamental understanding and magnetoresistive device applications of TI and small bandgap semiconductor materials.