Evidence for topological surface states in epitaxial Bi2Se3 thin film grown by pulsed laser deposition through magneto-transport measurements

We report epitaxial growth via domain matching epitaxy of Bi2Se3 thin films on Al2O3 (0 0 0 1) substrates with over 13% lattice misfit and critical thickness less than one monolayer. X-ray and electron diffraction patterns confirm that the layers are epitaxial with (0 0 0 1) Bi2Se3 || (0 0 0 1) Al2O3 and [ 2 1 ¯ 1 ¯ 0 ] Bi2Se3 || [ 2 1 ¯ 1 ¯ 0 ] Al2O3 (or) [ 2 1 ¯ 1 ¯ 0 ] Bi2Se3 || [ 1 1 2 ¯ 0 ] Al2O3 without the presence of an interfacial pseudomorphic layer. X-ray photoemission spectroscopy reveals that the films are Se-deficient, in agreement with electrical transport data showing n-type carriers and metallic behavior. Magneto-resistance (MR) measurements show a cusp feature corresponding to weak antilocalization and linear-MR shows a non-saturating trend up to 9 T. These results suggest topological surface states in PLD-grown Bi2Se3 films.