Quantum Oscillations and Chiral Anomaly in a Bi 0.96 Sb 0.04 Single Crystal

B i 1 - x S b x alloys are of special significance in topological insulator research. Here we focus on the Bi 0.96 Sb 0.04 alloy in which the conduction band edge just touches the valence band edge. Transport measurements show quantum oscillations in the longitudinal (Shubnikov–de Haas effect) and transverse magnetoresistance originating from a spheroidal Fermi surface pocket. Further investigation of the longitudinal magnetoresistance for the magnetic field parallel to the electrical current shows a small nonmonotonic magnetoresistance that is attributed to a competition of weak-antilocalization effects and a topological term related to the chiral anomaly.