Magneto-Transport Properties of Insulating Bulk States in Bi(111) Films

Magneto-transport properties of insulating bulk states in Bi(111) films are systematically investigated under the parallel field (B_||). We find that the magnetotransport of the B_|| field is a more powerful tool to distinguish the bulk states and the surface states. A large magnetoresistance (MR) up to 20% in the B_|| field is induced by the insulating bulk states for the suppression of the backward scattering. With the increasing thickness, a positive MR(B_||) from magnetic induced boundary scattering appears in the semimetal films. As the thickness is reduced to 10 nm, the positive MR(B_||) is induced by weak anti-localization from the surface states.