Nearly Free Electron States in Graphene Nanoribbon Superlattices

TL;DR

This paper investigates nearly free electron states in graphene nanoribbon superlattices, revealing two types of NFE states and proposing a new electron doping method for potential transistor applications.

Contribution

It provides a systematic first-principles analysis and introduces a simple model to understand NFE states, along with a novel doping-based transport channel.

Findings

Identification of two types of NFE states in graphene nanoribbon superlattices

Development of a simple Kronig-Penney potential model for NFE states

Proposal of an atom-scattering-free NFE transport channel via electron doping

Abstract

Nearly free electron (NFE) state is an important kind of unoccupied state in low dimensional systems. Although it is intensively studied, a clear picture on its physical origin and its response behavior to external perturbations is still not available. Our systematic first-principles study based on graphene nanoribbon superlattices suggests that there are actually two kinds of NFE states, which can be understood by a simple Kronig-Penney potential model. An atom-scattering-free NFE transport channel can be obtained via electron doping, which may be used as a conceptually new field effect transistor.