Condensed Matter Seminar: Topological phases of a dimerized Fermi-Hubbard model for dopant nano-lattices in silicon

Motivated by recent advances in fabricating artificial lattices especially dopant atoms in silicon and their promise for quantum simulation of topological materials, we theoretically study the one-dimensional dimerized Fermi-Hubbard model. We show how the topological phases at half-filling can be characterized by a reduced Zak phase defined based on the reduced density matrix of each spin subsystem. Signatures of bulk-boundary correspondence are observed in the triplon excitation of the bulk and the edge states of uncoupled spins at the boundaries. At quarter-filling we show that owing to the presence of the Hubbard interaction the system can undergo a transition to the topological state of the spinless Su-Schrieffer-Heeger model with the application of a moderate-strength external magnetic field. We propose an experimental realization with a chain of dopant atoms in silicon or gate-defined quantum dots in GaAs where the transition can be probed by measuring the tunneling current through the many-body state of the chain.

References:

Le, Fisher, Ginossar, PRB 96, 245406 (2017)

Le, Fisher, Curson, Ginossar, npj Quantum Information 6:24 (2020)