Magnetic Quantum Oscillations in Single Bi Nanowires

Our study presents the experimental measurements of Aharonov-Bohm (AB) oscillations on single Bi nanowires with diameter d < 80 nm. The single nanowire samples prepared by the Ulitovsky technique were cylindrical single crystals with (<10(1)over bar1>) orientation along the wire axis. Due to semimetal-to-semiconductor transformation and high density of surface states, Bi nanowire (d similar to 50 nm) effectively turns into a conducting tube. The oscillations of longitudinal magnetoresistance (MR) of Bi nanowires with two periods Delta B-1 similar to Phi(0) and Delta B-2 similar to Phi(0)/2 were observed, where Phi(0) = h/e is the flux quantum. From B similar to 8 T down to B = 0 the extremums of Phi(0)/2 oscillations are shifted up to 3 pi at B = 0 which is the manifestation of the Berry phase shift due to electron moving in nonuniform magnetic field. The derivative of MR for a 55 nm bismuth nanowire was measured at various inclined angles. An interpretation of the MR oscillations is presented.