Spin Selectivity in Electron Transmission Through Self-Assembled Monolayers of Double-Stranded DNA

TLDR

Spin effects in electron transfer are typically observed only in magnetic materials or systems containing heavy atoms that enable spin‑orbit coupling. This study demonstrates spin‑selective electron transmission through self‑assembled monolayers of double‑stranded DNA on gold. Spin polarizations exceeding 60 % at room temperature were measured with a Mott polarimeter, even with unpolarized light, and the efficiency increased with DNA length and organization, surpassing other known spin filters.

Abstract

In electron-transfer processes, spin effects normally are seen either in magnetic materials or in systems containing heavy atoms that facilitate spin-orbit coupling. We report spin-selective transmission of electrons through self-assembled monolayers of double-stranded DNA on gold. By directly measuring the spin of the transmitted electrons with a Mott polarimeter, we found spin polarizations exceeding 60% at room temperature. The spin-polarized photoelectrons were observed even when the photoelectrons were generated with unpolarized light. The observed spin selectivity at room temperature was extremely high as compared with other known spin filters. The spin filtration efficiency depended on the length of the DNA in the monolayer and its organization.