Observation of Aharonov-Bohm and Al'tshuler-Aronov-Spivak oscillations in the background of universal conductance fluctuations in silicon nanowires

Nano-Scale Transport Physics Laboratory, School of Physics, and DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand - Johannesburg, South Africa

^(a) Somnath.Bhattacharyya@wits.ac.za

Received: 21 September 2015
Accepted: 23 February 2016

Abstract

Magnetoresistance (MR) oscillations of multiple periodicities are recorded in singly connected silicon nanowires of diameter . At 100 K we observe oscillations of periodicity and 0.444 T corresponding to h/e and Aharonov-Bohm (AB) oscillations, whereas at 10 K we record periodicities of 0.98 T, 0.49 T and 0.25 T corresponding to h/e, (Al'tshuler-Aronov-Spivak (AAS)) and oscillations. At 2.5 K we find magnetoresistance oscillations with multiple periodicities of 1.3 T, 0.52 T, and 0.325 T corresponding to AB and AAS oscillations. The and peaks can be attributed to the interference of time-reversed paths originating from the core orbits that scatter coherently on the surface of the nanowires multiple times. We also observed 20 mT and 60 mT oscillations of small amplitude superimposed on a quasi-periodic background which we attribute to the quantum interference of special surface states associated with skipping orbits that propagate quasi-ballistically. The aperiodic fluctuations in the MR at all temperatures are universal conductance fluctuations (UCF) originating from randomly spaced impurity scattering in the core of the nanowire.