Differential Conductance Fluctuation of Curved Nanographite Sheets in the Mesoscopic Regime

TL;DR

This study investigates conductance fluctuations in curved nano-graphite sheets across a wide temperature range, revealing size-dependent behavior linked to quantum coherence and energy bandgap effects.

Contribution

It provides new insights into the temperature-dependent conductance fluctuations in nano-graphite sheets, highlighting the effects of device size and transport regimes.

Findings

Fluctuations are temperature-dependent and prominent in smaller gaps.

Conductance fluctuations are suppressed above 4.2 K in larger gaps.

Crossover from coherent to diffusive transport explains the suppression.

Abstract

Excess conductance fluctuations with peculiar temperature-dependence from 1.4 to 250 K were observed in curved nano-graphite sheets with an electrode gap length of 300 and 450 nm, whereas the conductance fluctuation is greatly suppressed above 4.2 K when the electrode gap length increases to 800 and 1000 nm. The former is discussed in the context of the presence of a small energy bandgap in the nano-graphite sheets, while the latter is attributed to the crossover from coherent transport to diffusive transport regime.