Guiding of Electrons in a Few Mode Ballistic Graphene Channel

TL;DR

This paper demonstrates guiding charge carriers in a suspended ballistic graphene channel using electrostatic gating, showing quantized conductance steps as the number of modes is reduced, supported by theoretical calculations.

Contribution

It introduces a method to control electron flow in graphene channels via electrostatic gating, enabling mode manipulation and conductance quantization.

Findings

Observation of conductance steps corresponding to mode reduction

Complete depletion of the channel confirmed by measurements

Transport calculations support experimental results

Abstract

In graphene, the extremely fast charge carriers can be controlled by electron-optical elements, such as waveguides, in which the transmissivity is tuned by the wavelength. In this work, charge carriers are guided in a suspended ballistic few-mode graphene channel, defined by electrostatic gating. By depleting the channel, a reduction of mode number and steps in the conductance are observed, until the channel is completely emptied. The measurements are supported by tight-binding transport calculations including the full electrostatics of the sample.