Intrinsic Rashba coupling due to Hydrogen bonding in DNA

TL;DR

This paper develops an analytical model showing that hydrogen bonding significantly enhances intrinsic Rashba spin-orbit coupling in DNA, influencing spin-selective transport phenomena in biological molecules.

Contribution

It introduces a new analytical approach quantifying hydrogen bonding's role in Rashba coupling, surpassing previous estimates and highlighting its importance in biological chiral molecules.

Findings

Rashba coupling is ten times larger than previous estimates.

Hydrogen bonding plays a key role in spin-active effects in DNA.

Similar effects are expected in hydrogen-bonded oligopeptides.

Abstract

We present an analytical model for the role of hydrogen bonding on the spin-orbit coupling of model DNA molecule. Here we analyze in detail the electric fields due to the polarization of the Hydrogen bond on the DNA base pairs and derive, within tight binding analytical band folding approach, an intrinsic Rashba coupling which should dictate the order of the spin active effects in the Chiral-Induced Spin Selectivity (CISS) effect. The coupling found is ten times larger than the intrinsic coupling estimated previously and points to the predominant role of hydrogen bonding in addition to chirality in the case of biological molecules. We expect similar dominant effects in oligopeptides, where the chiral structure is supported by hydrogen-bonding and bears on orbital carrying transport electrons.