Quantum-relativistic matter is ubiquitous in nature; however it is notoriously difficult to probe. The ease with which external electric and magnetic fields can be introduced in graphene opens a door to creating a table-top prototype of strongly confined relativistic matter. Here, through a detailed spectroscopic mapping, we provide a spatial visualization of the interplay between spatial and magnetic confinement in a circular graphene resonator. We directly observe the development of a multi-tiered "wedding cake"-like structure of concentric regions of compressible/incompressible quantum Hall states, a signature of electron interactions in the system. Solid-state experiments can therefore yield insights into the behaviour of quantum-relativistic matter under extreme conditions.
@article{arxiv.1810.00214,
title = {Interaction Driven Quantum Hall Wedding cake-like Structures in Graphene Quantum Dots},
author = {Christopher Gutiérrez and Daniel Walkup and Fereshte Ghahari and Cyprian Lewandowski and Joaquin F. Rodriguez-Nieva and Kenji Watanabe and Takashi Taniguchi and Leonid S. Levitov and Nikolai B. Zhitenev and Joseph A. Stroscio},
journal= {arXiv preprint arXiv:1810.00214},
year = {2018}
}