Charge distribution in C$_{60}$ crystal doped by electric field

TL;DR

This paper models charge distribution in C60 crystal FETs, revealing that injected charges predominantly localize on the surface layer with a distribution independent of total charge, differing from previous tight-binding results.

Contribution

A simple model for charge distribution in C60 FET structures is proposed, highlighting surface charge localization and its independence from total injected charge.

Findings

Charge density peaks at the surface layer.

Charge distribution is exponential with depth.

Surface charge localization differs from tight-binding predictions.

Abstract

The calculations of the charge distribution in C$_{60}$-based FET structure are presented. A simple model is proposed to describe the distribution of the injected electrons or holes between two-dimensional layers. The calculations show that the relative charge distribution between the layers turns to be independent on the total amount of injected charges. The charge density is maximal on the surface layer and drops exponentially with the depth increase. The relative amounts of injected charge involved in the top layer are 73 and 64 per cent in the case of electron and hole injection, respectively. Thus, the charge localization on the crystal surface turns to be markedly different from near complete one that was obtained earlier within tight- binding model for the charge concentration providing superconductivity.