Coherent heteroepitaxy of Bi{sub 2}Se{sub 3} on GaAs (111)B

We report the heteroepitaxy of single crystal thin films of Bi{sub 2}Se{sub 3} on the (111)B surface of GaAs by molecular beam epitaxy. We find that Bi{sub 2}Se{sub 3} grows highly c-axis oriented, with an atomically sharp interface with the GaAs substrate. By optimizing the growth of a very thin GaAs buffer layer before growing the Bi{sub 2}Se{sub 3}, we demonstrate the growth of thin films with atomically flat terraces over hundreds of nanometers. Initial time-resolved Kerr rotation measurements herald opportunities for probing coherent spin dynamics at the interface between a candidate topological insulator and a large class of GaAs-based heterostructures.