Bi nanowires: Magnetism and the semimetal-to- semiconductor transition

Cantilever magnetometry experiments were performed on arrays of Bi nanowires of various diameters both on the semimetal and semiconductor side of the semimetal-tosemiconductor transition (SMSC) that is predicted to occur for diameters of approximately 50 nm. Our 270 nm nanowire samples, which are on the semimetal side of the SMSC transition, exhibit strong dHvA oscillations that can be interpreted by considering crystalline orientation and size effects and a large magnetization. Arrays of wires with diameters near or below the SMSC (60 and 36 nm) have dramatically reduced magnetizations per volume, and do not exhibit dHvA oscillations, consistent with a reduction in free carriers due to the SMSC.