We observed pronounced angular-dependent magnetoresistance (MR) oscillations
in a high-quality Bi2Se3 single crystal with the carrier density of 5x10^18
cm^-3, which is a topological insulator with residual bulk carriers. We show
that the observed angular-dependent oscillations can be well simulated by using
the parameters obtained from the Shubnikov-de Haas oscillations, which
clarifies that the oscillations are solely due to the bulk Fermi surface. By
completely elucidating the bulk oscillations, this result paves the way for
distinguishing the two-dimensional surface state in angular-dependent MR
studies in Bi2Se3 with much lower carrier density. Besides, the present result
provides a compelling demonstration of how the Landau quantization of an
anisotropic three-dimensional Fermi surface can give rise to pronounced
angular-dependent MR oscillations.Comment: 5 pages, 5 figure