Quantum transport in double-gated graphene devices

TL;DR

This paper investigates quantum transport phenomena in double-gated graphene devices, revealing tunable electronic properties and quantized conductance in various graphene layers under different magnetic field conditions.

Contribution

It provides new experimental insights into tunable band gaps and conductance quantization in suspended double-gated graphene structures.

Findings

Observation of tunable pnp junctions with charge density control

Detection of quantized conductance at integer and fractional values

Agreement of experimental data with edge state equilibration models

Abstract

Double-gated graphene devices provide an important platform for understanding electrical and optical properties of graphene. Here we present transport measurements of single layer, bilayer and trilayer graphene devices with suspended top gates. In zero magnetic fields, we observe formation of pnp junctions with tunable polarity and charge densities, as well as a tunable band gap in bilayer graphene and a tunable band overlap in trilayer graphene. In high magnetic fields, the devices' conductance are quantized at integer and fractional values of conductance quantum, and the data are in good agreement with a model based on edge state equilibration at pn interfaces.