Novel electronic wave interference patterns in nanographene sheets

TL;DR

This paper investigates superperiodic electronic interference patterns in nanographene sheets observed via STM, explaining their origin through a static linear potential and band structure effects, with theoretical and experimental agreement.

Contribution

It introduces a theoretical model explaining long-distance interference patterns in nanographene using a static linear potential and band structure considerations.

Findings

Oscillation period decreases with distance, matching experimental data.

Estimated potential difference of 1.3 eV over 200 nm.

Long-distance oscillations originate from graphene's band structure.

Abstract

Superperiodic patterns with a long distance in a nanographene sheet observed by STM are discussed in terms of the interference of electronic wave functions. The period and the amplitude of the oscillations decrease spatially in one direction. We explain the superperiodic patterns with a static linear potential theoretically. In the k-p model, the oscillation period decreases, and agrees with experiments. The spatial difference of the static potential is estimated as 1.3 eV for 200 nm in distance, and this value seems to be reasonable in order that the potential difference remains against perturbations, for example, by phonon fluctuations and impurity scatterings. It turns out that the long-distance oscillations come from the band structure of the two-dimensional graphene sheet.