DNA mechanical deformations and chiral spin selectivity

TL;DR

This study demonstrates that mechanical deformations such as stretching and compression of DNA can tune spin selectivity and filtering gaps, revealing a link between DNA geometry and spin-orbit coupling effects.

Contribution

It introduces a deformation-dependent model of spin selectivity in DNA, showing how mechanical strains influence spin-orbit interactions and transport properties.

Findings

Spin selectivity varies with DNA deformation.

Stretching enhances spin filtering effects.

Deformation alters the spin-orbit coupling strength.

Abstract

The strength of the spin-orbit interaction relevant to transport in a low dimensional structure depends critically on the relative geometrical arrangement of current carrying orbitals. Recent tight-binding orbital models for spin transport in DNA-like molecules, have surmised that the band spin-orbit coupling arises from the particular angular relations between orbitals of neighboring bases on the helical chain. Such arrangement could be probed by inducing deformations in the molecule in a conductive probe AFM type setup, as it was recently reported by Kiran, Cohen and Naaman\cite{Kiran}. Here we report deformation dependent spin selectivity when a double strand DNA model is compressed or stretched. We find that the equilibrium geometry is not optimal with respect to the SO coupling strength and thus spin selectivity can be tuned by deformations. The latter can be increased by stretching the helical structure taking into account its elastic properties through the Poisson ratio. The spin filtering gap is also found to be tunable with uniaxial deformations.