Coherent Jetting behind a gate-defined Channel in Bilayer Graphene

TL;DR

This paper reports the observation of electron jets emanating from a narrow split-gate channel in bilayer graphene, revealing how bandstructure effects like trigonal warping influence ballistic and valley-dependent transport.

Contribution

It provides the first experimental evidence of electron jetting in bilayer graphene linked to bandstructure effects, advancing understanding of quantum transport phenomena.

Findings

Electron jets are observed with a 60° angle between them.

Jets are related to trigonal warping in bilayer graphene.

Implications for valley-dependent and ballistic transport in devices.

Abstract

Graphene has evolved as a platform for quantum transport that can compete with the best and cleanest semiconductor systems. Recently, many interesting local properties of carrier transport in graphene have been investigated by various scanning probe techniques. Here, we report on the observation of distinct electronic jets emanating from a narrow split-gate defined channel in bilayer graphene. We find that these jets, which are visible via their interference patterns, occur predominantly with an angle of 60{\deg} between each other. This observation is related to the specific bandstructure of bilayer graphene, in particular trigonal warping, which leads to a valley-dependent selection of momenta for low-energy conduction channels. This experimental observation of electron jetting has consequences for carrier transport in graphene in general as well as for devices relying on ballistic and valley selective transport.