Spin States in Graphene Quantum Dots

TL;DR

This paper studies the spin states and magnetic properties of small graphene quantum dots by measuring ground and excited state transport, revealing spin filling sequences and Zeeman splitting consistent with theoretical expectations.

Contribution

It provides experimental insights into spin filling and Zeeman splitting in graphene quantum dots, highlighting exchange interactions and g-factor measurements.

Findings

Spin filling sequence observed in graphene quantum dots

Zeeman splitting measured with g-factor approximately 2

Exchange interaction effects are consistent with theoretical predictions

Abstract

We investigate ground and excited state transport through small (d = 70 nm) graphene quantum dots. The successive spin filling of orbital states is detected by measuring the ground state energy as a function of a magnetic field. For a magnetic field in-plane of the quantum dot the Zemann splitting of spin states is measured. The results are compatible with a g-factor of 2 and we detect a spin-filling sequence for a series of states which is reasonable given the strength of exchange interaction effects expected for graphene.