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arXiv · 1106.3215

Two-dimensional Mott-Hubbard electrons in an artificial honeycomb lattice

A. Singha·M. Gibertini·B. Karmakar·S. Yuan·M. Polini·G. Vignale·M. I. Katsnelson·A. Pinczuk·L. N. Pfeiffer·K. W. West·V. Pellegrini
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Abstract

Electrons in artificial lattices enable explorations of the impact of repulsive Coulomb interactions in a tunable system. We have trapped two-dimensional electrons belonging to a gallium arsenide quantum well in a nanofabricated lattice with honeycomb geometry. We probe the excitation spectrum in a magnetic field identifying novel collective modes that emerge from the Coulomb interaction in the artificial lattice as predicted by the Mott-Hubbard model. These observations allow us to determine the Hubbard gap and suggest the existence of a novel Coulomb-driven ground state. This approach offers new venues for the study of quantum phenomena in a controllable solid-state system.

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A. Singha, M. Gibertini, B. Karmakar, S. Yuan, M. Polini, G. Vignale, M. I. Katsnelson, A. Pinczuk, L. N. Pfeiffer, K. W. West, V. Pellegrini. 2011-06-16. Two-dimensional Mott-Hubbard electrons in an artificial honeycomb lattice. https://doi.org/10.1126/science.1204333

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