Disorder-resilient transport through dopant arrays in silicon

TL;DR

This paper demonstrates that transport in disordered dopant arrays in silicon remains robust due to strong correlations, with current following shortest paths, simplifying device characterization despite disorder.

Contribution

The study introduces a theoretical approach combining Hubbard model diagonalization and Green's functions to analyze transport in disordered dopant arrays, revealing resilience to disorder.

Findings

Transport features are highly resilient to disorder.

Current follows shortest paths avoiding obstacles.

Array behavior resembles parallel chains with Coulomb coupling.

Abstract

Chains and arrays of phosphorus donors in silicon have recently been used to demonstrate dopant-based quantum simulators. The dopant disorder present in fabricated devices must be accounted for. Here, we theoretically study transport through disordered donor-based $3\times 3$ arrays that model recent experimental results. We employ a theory that combines the exact diagonalization of an extended Hubbard model of the array with a non-equilibrium Green's function formalism to model transport in interacting systems. We show that current flow through the array and features of measured stability diagrams are highly resilient to disorder. We interpret this as an emergence of uncomplicated behavior in the multi-electron system dominated by strong correlations, regardless of array filling, where the current follows the shortest paths between source and drain sites that avoid possible obstacles. The reference $3\times 3$ array has transport properties very similar to three parallel 3-site chains coupled only by interchain Coulomb interaction, which indicates a challenge in characterizing such devices.