Impurities in a Biased Graphene Bilayer

TL;DR

This paper investigates how impurities and mid-gap states in a biased graphene bilayer can be controlled via an electric field, affecting the electronic properties and impurity band formation.

Contribution

It introduces a method to externally control impurity states and band gap renormalization in biased graphene bilayers using the coherent potential approximation.

Findings

Impurity states' localization lengths and binding energies are tunable by electric bias.

Band gap renormalization occurs due to impurity effects.

Impurity bands form at finite impurity concentrations.

Abstract

We study the problem of impurities and mid-gap states in a biased graphene bilayer. We show that the properties of the bound states, such as localization lengths and binding energies, can be controlled externally by an electric field effect. Moreover, the band gap is renormalized and impurity bands are created at finite impurity concentrations. Using the coherent potential approximation we calculate the electronic density of states and its dependence on the applied bias voltage.