Record surface state mobility and quantum Hall effect in topological insulator thin films via interface engineering

Thin films of topological insulators (TIs) with conduction dominated by high mobility topological surface state (TSS) channel have been difficult to achieve due to increased material defects, thus making it difficult to probe TIs in quantum regime. Here by utilizing a structurally matched buffer layer based on In$_{2}$Se$_{3}$, we have achieved Bi$_{2}$Se$_{3}$ films with low defect density resulting in `order of magnitude' improvement in mobilities and carrier densities. This has led to TSS dominated transport and first observation of quantum Hall effect in Bi$_{2}$Se$_{3}$.