# Excited states in bilayer graphene quantum dots

## TL;DR

This study investigates the electronic states of bilayer graphene quantum dots, revealing unique spin and valley configurations, and quantifying exchange energies and g-factors through detailed spectroscopy analysis.

## Contribution

It provides the first detailed analysis of two-particle spectra in bilayer graphene quantum dots including spin and valley effects, highlighting differences from other quantum dot systems.

## Key findings

- Ground state is a spin-triplet and valley-singlet
- Exchange energy quantified as 0.35 meV
- Valley and spin g-factors measured as 36 and 2

## Abstract

We report on ground- and excited state transport through an electrostatically defined few-hole quantum dot in bilayer graphene in both parallel and perpendicular applied magnetic fields. A remarkably clear level scheme for the two-particle spectra is found by analyzing finite bias spectroscopy data within a two-particle model including spin and valley degrees of freedom. We identify the two-hole ground-state to be a spin-triplet and valley-singlet state. This spin alignment can be seen as Hund's rule for a valley-degenerate system, which is fundamentally different to quantum dots in carbon nano tubes and GaAs-based quantum dots. The spin-singlet excited states are found to be valley-triplet states by tilting the magnetic field with respect to the sample plane. We quantify the exchange energy to be 0.35meV and measure a valley and spin g-factor of 36 and 2, respectively.