Characterization of the size and position of electron-hole puddles at a graphene p-n junction

TL;DR

This paper investigates how electron-hole puddles affect electrical transport in graphene p-n junctions, providing methods to characterize their size and position through conductance measurements influenced by magnetic field and electron density.

Contribution

The study introduces a numerical and analytical approach to determine the size and position of electron-hole puddles in graphene p-n junctions based on conductance behavior.

Findings

Electron-hole puddles disrupt snake state transport in graphene.

Conductance dependence on magnetic field reveals puddle characteristics.

Analytical formula links puddle position with conductance features.

Abstract

The effect of an electron-hole puddle on the electrical transport when governed by snake states in a bipolar graphene structure is investigated. Using numerical simulations we show that information on the size and position of the electron-hole puddle can be obtained using the dependence of the conductance on magnetic field and electron density of the gated region. The presence of the scatterer disrupts snake state transport which alters the conduction pattern. We obtain a simple analytical formula that connects the position of the electron-hole puddle with features observed in the conductance. Size of the electron-hole puddle is estimated from the magnetic field and gate potential that maximizes the effect of the puddle on the electrical transport.