Magnetic Quantum Oscillations in Single Bi Nanowires

Abstract

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 $\bar{1}$ 1) orientation along the wire axis. Due to semimetal-to-semiconductor transformation and high density of surface states, Bi nanowire (d∼50 nm) effectively turns into a conducting tube. The oscillations of longitudinal magnetoresistance (MR) of Bi nanowires with two periods Δ B 1∼Φ 0 and Δ B 2∼Φ 0/2 were observed, where Φ 0=h/e is the flux quantum. From B∼8 T down to B=0 the extremums of Φ 0/2 oscillations are shifted up to 3π 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.