Revealing Correlated Electron Behavior in Fermi-Hubbard Arrays through Spin-Resolved Transport

Analog quantum simulators based on phosphorus-doped silicon quantum dot arrays have recently been used to investigate extended Fermi-Hubbard models [1]. A key open question is whether transport measurements in silicon-based two-dimensional nanoscale arrays, when coupled to metallic leads, can provide insight into the underlying many-body physics [2]. It remains to be determined whether spin-dependent transport properties can reveal signatures of strong onsite and intersite Coulomb interactions. In this work, we numerically examine spin-resolved transport of various two-dimensional quantum dot array geometries under two distinct coupling regimes: (i) weak coupling to ferromagnetic leads, and (ii) strong coupling to similarly polarized leads, which induces spin-dependent renormalization of the array’s local density of states. Using the steady-state nonequilibrium Green’s function formalism, we analyze both two-terminal and four-terminal configurations to uncover the role of many-body wavefunction interference in determining the transport response. Our results demonstrate that spin-polarized transport measurements in phosphorus dopant-based silicon quantum dot arrays can serve as a diagnostic tool for probing many-body effects in representative extended Fermi-Hubbard models.

[1] X. Wang, E. Khatami, F. Fei, J. Wyrick, P. Namboodiri, R. Kashid, A. F. Rigosi, G. Bryant, and R. Silver, Nat. Commun. 13, 6824 (2022).

[2] M. Gawełczyk, G. W. Bryant, and M. Zieliński, arXiv:2405.05217.