Observation of Shubnikov de Haas and Aharanov-Bohm oscillations in silicon nanowires

TL;DR

This study observes and analyzes quantum oscillations, including Shubnikov de Haas and Aharonov-Bohm effects, in silicon nanowires at various temperatures and magnetic fields, revealing detailed electronic properties and edge state behaviors.

Contribution

It provides the first detailed experimental observation and analysis of both SdH and AB oscillations in silicon nanowires, elucidating edge state dynamics and quantum confinement effects.

Findings

Detection of fine oscillations superimposed on larger periodic oscillations.

Derived electron effective mass and carrier density ranges.

At low temperatures, oscillation amplitude remains invariant due to size confinement and impurity effects.

Abstract

We record fine oscillations of 20 to 60 mT superimposed on larger oscillations having periodicity ~ 2 T at temperatures up to 100 K and fields up to 10 T from silicon nanowires. Having confirmed that these features appear from the edge states associated with skipping orbits at nanowire edges and confined pure orbits in the interior of the nanowires we derive electron effective mass of 0.001 me to 0.006 me, carrier lifetime in the range 3 to 19 fs and carrier density that varies from 2x10^11 cm^-2 to 9x10^12 cm^-2. However, at low temperature the observed oscillation amplitude invariant of the field is attributed to not only a strong size confinement and the pinning of orbits by impurities but also Aharanov Bohm (AB) oscillations due to edge-states that propagate quasi-ballistically through the nanowire. The overall oscillation on a linear positive magnetoresistance background can be attributed to temperature-dependent crossover of Shubnikov de Haas oscillations (SdHO) and AB oscillations in silicon nanowires.