Tunable metal-insulator transition in double-layer graphene heterostructures

TL;DR

This study demonstrates a tunable metal-insulator transition in double-layer graphene heterostructures, showing how interlayer interactions and external fields influence electronic localization and conductivity.

Contribution

It reveals the intrinsic localization behavior in neutral graphene with disorder, controlled by interlayer coupling and external parameters, advancing understanding of 2D electronic phase transitions.

Findings

Resistivity diverges at low temperatures for large carrier densities

Magnetic field suppresses the localization effect

Reducing carrier density in the adjacent layer restores metallic behavior

Abstract

We report a double-layer electronic system made of two closely-spaced but electrically isolated graphene monolayers sandwiched in boron nitride. For large carrier densities in one of the layers, the adjacent layer no longer exhibits a minimum metallic conductivity at the neutrality point, and its resistivity diverges at low temperatures. This divergence can be suppressed by magnetic field or by reducing the carrier density in the adjacent layer. We believe that the observed localization is intrinsic for neutral graphene with generic disorder if metallic electron-hole puddles are screened out.