Manipulating electron-spin polarization using cysteine-DNA chiral conjugates.

Abstract

The chiral molecules are potential generators of high spin-filters due to their inherent inversion asymmetric helical electric field. We report a controlled spin-selective transmission of electrons through self-assembled monolayers of 15 base-paired double-stranded deoxyribonucleic acid functionalized with two enantiomeric cysteine molecules on gold explored through the quantum mechanical tunneling effect. We observed a controlled spin polarization of 33% with dextro-cysteine, whereas a mere 8% was observed with levo-cysteine molecules using these functionalizations at room temperature. The manipulation of electron's spin merely through such a small molecule could lead to significant advancement in the spin-dependent charge transport phenomena and related applications.