Topological surface states on high-index Bi$_{2}$Se$_{3}$ epifilms grown by molecular-beam epitaxy on InP(001)

We use MBE to successfully grow a high-index Bi$_{2}$Se$_{3}$ (221) epifilm on InP(001) substrate. To facilitate growth of Bi$_{2}$Se$_{3}$ (221) on InP(001), the substrate has to undergo a careful thermal treatment. XRD and LEED measurements affirm the film to be of Bi$_{2}$Se$_{3}$ (221).The ARPES experiments on such a Bi$_{2}$Se$_{3}$(221) sample reveal unambiguously the linear dispersed surface states. In addition, the Fermi surface is elliptical rather than the more symmetrical one on Bi$_{2}$Se$_{3}$(111). Electrical transport studies of such (221) Bi$_{2}$Se$_{3}$ samples also show an anisotropy in two perpendicular directions in the plane of the surface. The longitudinal resistivity along the ``transverse'' direction is 1.9 $\sim$ 4.4 times higher than that along the ``parallel'' direction, and their ratios also depend on temperature from 2K to 300K. Hall resistances show non-linear field dependence at high temperature, implying multiband conduction.