Gate-defined electron-hole double dots in bilayer graphene

TL;DR

This paper demonstrates gate-controlled electron-hole double quantum dots in bilayer graphene, showcasing advanced fabrication techniques that enable precise confinement, control, and magnetic field studies of quantum states.

Contribution

It reports the first realization and characterization of gate-defined electron-hole double dots in bilayer graphene with high control and tunability.

Findings

Successful electrostatic confinement of carriers in bilayer graphene.

Observation of Zeeman spin splitting with g-factor of two.

Implementation of two similar double-dot systems with comparable energy scales.

Abstract

We present gate-controlled single, double, and triple dot operation in electrostatically gapped bilayer graphene. Thanks to the recent advancements in sample fabrication, which include the encapsulation of bilayer graphene in hexagonal boron nitride and the use of graphite gates, it has become possible to electrostatically confine carriers in bilayer graphene and to completely pinch-off current through quantum dot devices. Here, we discuss the operation and characterization of electron-hole double dots. We show a remarkable degree of control of our device, which allows the implementation of two different gate-defined electron-hole double-dot systems with very similar energy scales. In the single dot regime, we extract excited state energies and investigate their evolution in a parallel magnetic field, which is in agreement with a Zeeman-spin-splitting expected for a g-factor of two.