Chirality driven topological electronic structure of DNA-like materials

TL;DR

This paper uncovers a topological orbital texture in chiral molecules like DNA, explaining their ability to polarize spins and induce spin-selective effects, with implications for chiral and achiral materials.

Contribution

It introduces the concept of orbital polarization effect (OPE) driven by chirality, linking topological orbital textures to spin polarization in chiral molecules.

Findings

Orbital texture is a topological feature induced by molecular chirality.

OPE enables spin polarization in chiral molecules via spin-orbit interaction.

Predictions extend OPE-induced spin selectivity to achiral inversion-breaking materials.

Abstract

Topological aspects of the geometry of DNA and similar chiral molecules have received a lot of attention, while the topology of their electronic structure is less explored. Previous experiments have revealed that DNA can efficiently filter spin-polarized electrons between metal contacts, a process called chiral-induced spin-selectivity (CISS). However, the underlying correlation between chiral structure and electronic spin remains elusive. In this work, we reveal an orbital texture in the band structure, a topological characteristic induced by the chirality. We find that this orbital texture enables the chiral molecule to polarize the quantum orbital. This orbital polarization effect (OPE) induces spin polarization assisted by the spin-orbit interaction from a metal contact and leads to magnetorestistance and chiral separation. The orbital angular momentum of photoelectrons also plays an essential role in related photoemission experiments. Beyond CISS, we predict that OPE can induce spin-selective phenomena even in achiral but inversion-breaking materials.