Jonathan Wyrick(1), Fan Fei(1,2), Ehsan Khatami(4), Pradeep Namboodiri(1), Utsav(1), Joseph Fox(1,2), Garnett Bryant(1,3) and Richard Silver (1)
(1) Atom Scale Device Group, National Institute of Standards and Technology, Gaithersburg MD
(2) Department of Physics, University of Maryland, College Park, MD
(3) Joint Quantum Institute, University of Maryland, College Park, MD
(4) Department of Physics and Astronomy, San José State University, San José, CA
Dopant atoms imbedded in silicon and arranged with atomic precision in 3 dimensions enable construction of Hamiltonians for quantum simulation at the ultimate level of spatial detail: the atomic limit. For an atomically-defined simulation structure, the choice of dopant type, the number of dopants at a given site, and their configuration determine the physical characteristics of the local and long range electrostatic potential, tunnel coupling, and spin behavior. Nanometer scale highly doped STM patterned leads and gates can be aligned with atomic precision while e-beam fabricated electrodes, such as top-gates and ESR antennas, are placed with 10s to 100s of nanometer precision relative to the simulation structure, allowing for electrostatic tunability and coherent control/manipulation of the quantum states of the system.
At NIST, we are fabricating atomically-precise P devices in Si using scanning probe-based hydrogen depassivation lithography (HDL). We have built single atom transistors, few-donor/quantum dot devices, and arrayed few-donor devices, and have investigated these systems within the context of their application to analog quantum simulation. In particular, we have explored portions of the Hubbard model phase space using arrayed few-atom P clusters, whose properties such as magnetic ordering and Mott-like behavior are highly sensitive to the details of their atomic configurations. We use numerical calculations of an extended Fermi-Hubbard model (made possible by our choice of a small array size, 3×3) to simulate spin/charge occupation, the spatial distribution of the states of the many-body system, and magnetic correlations, for comparison and validation of the measurements made on the experimentally realized systems. In parallel we are developing more refined methods to interrogate these systems, such as spin manipulation and readout via RF reflectometry, using donor/quantum dot devices as targeted test structures. These efforts are aimed at establishing HDL fabricated dopant-in-Si devices as a useful, highly controlled platform for quantum simulation.