Current-driven mechanical motion of double stranded DNA results in structural instabilities and chiral-induced-spin-selectivity of electron transport

TL;DR

This study investigates how current-driven mechanical motion in double-stranded DNA influences its structural stability and enhances spin-selective electron transport, revealing potential experimental methods to monitor DNA dynamics.

Contribution

It introduces a mixed quantum-classical approach to model DNA's mechanical and electronic interactions, highlighting the impact of mechanical motion on spin transport and stability.

Findings

Mechanical motion modifies DNA potential, creating bistability at high voltages.

Mechanical motion enhances spin polarization of electron current by 9%.

Current noise measurements can detect mechanical instabilities in DNA.

Abstract

Chiral-induced-spin-selectivity of electron transport and its interplay with DNA's mechanical motion is explored in a double stranded DNA helix with spin-orbit-coupling. The mechanical degree of freedom is treated as a stochastic classical variable experiencing fluctuations and dissipation induced by the environment as well as force exerted by nonequilibrium, current-carrying electrons. Electronic degrees of freedom are described quantum mechanically using nonequilibrium Green's functions. Nonequilibrium Green's functions are computed along the trajectory for the classical variable taking into account dynamical, velocity dependent corrections. This mixed quantum-classical approach enables calculations of time-dependent spin-resolved currents. We showed that the electronic force may significantly modify the classical potential which, at sufficient voltage, creates a bistable potential with considerable effect on electronic transport. The DNA's mechanical motion has a profound effect on spin transport; it results in chiral-induced spin selectivity increasing spin polarisation of the current by 9% and also resulting in temperature-dependent current voltage characteristics. We demonstrate that the current noise measurement provides an accessible experimental means to monitor the emergence of mechanical instability in DNA motion. The spin resolved current noise also provides important dynamical information about the interplay between vibrational and spin degrees of freedom in DNA.