• Lahiri, Aritra
• Gharavi, Kaveh
• Muralidharan, Bhaskaran

Abstract

We explore various aspects of magnetoconductance oscillations in semiconductor nanowires, developing quantum transport models based on the nonequilibrium Green's function formalism. In the clean case, Aharonov-Bohm (AB, h /e ) oscillations are found to be dominant, contingent upon the surface confinement of electrons in the nanowire. We also numerically study disordered nanowires of finite length, extending the existing literature. By varying the nanowire length and disorder strength, we identify the transition where Al'tshuler-Aronov-Spivak (AAS, h /2 e ) oscillations start dominating, noting the effects of considering an open system. Moreover, we demonstrate how the relative magnitudes of the scattering length and the device dimensions govern the relative dominance of these harmonics with energy, revealing that the AAS oscillations emerge and start dominating from the center of the band, much higher in energy than the conduction band edge. We also show the ways of suppressing the oscillatory components (AB and AAS) to observe the nonoscillatory weak localization corrections, noting the interplay of scattering, incoherence/dephasing, the geometry of electronic distribution, and orientation of magnetic field. This is followed by a study of surface roughness which shows contrasting effects depending on its strength and type, ranging from magnetic depopulation to strong AAS oscillations. Subsequently, we show that dephasing causes a progressive degradation of the higher harmonics, explaining the reemergence of the AB component even in long and disordered nanowires. Lastly, we show that our model qualitatively reproduces the experimental magnetoconductance spectrum of Holloway et al. [Phys. Rev. B 91, 045422 (2015), 10.1103/PhysRevB.91.045422] reasonably well while demonstrating the necessity of spatial correlations in the disorder potential and dephasing....

Topics

• impedance spectroscopy
• surface
• semiconductor
• strength
• atomic absorpion spectrometry