Experimental realization of an extended Fermi-Hubbard model using a 2D lattice of dopant-based quantum dots

Xiqiao Wang; Ehsan Khatami; Fan Fei; Jonathan Wyrick; Pradeep Namboodiri; Ranjit Kashid; Albert F Rigosi; Garnett Bryant; Richard Silver

doi:10.1038/s41467-022-34220-w

Experimental realization of an extended Fermi-Hubbard model using a 2D lattice of dopant-based quantum dots

Nat Commun. 2022 Nov 11;13(1):6824. doi: 10.1038/s41467-022-34220-w.

Authors

Xiqiao Wang^{1

2

3}, Ehsan Khatami⁴, Fan Fei^{1

5}, Jonathan Wyrick¹, Pradeep Namboodiri¹, Ranjit Kashid^{1

6}, Albert F Rigosi¹, Garnett Bryant^{1

2}, Richard Silver⁷

Affiliations

¹ Atom Based Device Group, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
² Joint Quantum Institute, University of Maryland, College Park, MD, 20740, USA.
³ Rigetti Computing, Fremont, CA, 94538, USA.
⁴ Department of Physics and Astronomy, San José State University, San José, CA, 95192, USA.
⁵ Department of Physics, University of Maryland, College Park, MD, 20740, USA.
⁶ Center for Materials for Electronics Technology, Pune, 411008, India.
⁷ Atom Based Device Group, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA. Richard.silver@nist.gov.

Abstract

The Hubbard model is an essential tool for understanding many-body physics in condensed matter systems. Artificial lattices of dopants in silicon are a promising method for the analog quantum simulation of extended Fermi-Hubbard Hamiltonians in the strong interaction regime. However, complex atom-based device fabrication requirements have meant emulating a tunable two-dimensional Fermi-Hubbard Hamiltonian in silicon has not been achieved. Here, we fabricate 3 × 3 arrays of single/few-dopant quantum dots with finite disorder and demonstrate tuning of the electron ensemble using gates and probe the many-body states using quantum transport measurements. By controlling the lattice constants, we tune the hopping amplitude and long-range interactions and observe the finite-size analogue of a transition from metallic to Mott insulating behavior. We simulate thermally activated hopping and Hubbard band formation using increased temperatures. As atomically precise fabrication continues to improve, these results enable a new class of engineered artificial lattices to simulate interactive fermionic models.