Negative magnetoresistance in transverse and longitudinal magnetic fields in Bi nanowires

Abstract

In this work the measurements of longitudinal (LMR) and transverse magnetoresistance (TMR) in Bi wires with 50 <80 nm contains the negative region R(H) > R0 at T<5 K. This result was unexpected, because it is known that in bulk Bi samples the "giant" increase of magnetoresistance in the case H⊥I is observed. We calculate the conductivity of nanowires in longitudinal and transverse magnetic fields on the basis of the Cubo formula for the conductivity. We use the model of quantum wires with a parabolic potential in the plane orthogonal to the axis of the size-quantized system. According to the model of such TMR and LMR were experimentally observed in the Bi quantum wires (QW) with d<80nm. © 2009 IOP Publishing Ltd.