Insulator-metal transition in biased finite polyyne systems

TL;DR

This paper develops a variational non-equilibrium polaronic theory to study electronic transport in biased polyyne chains, predicting an insulator-metal transition driven by non-equilibrium charging effects.

Contribution

It introduces a novel variational framework for analyzing non-equilibrium electron-phonon interactions in finite molecular chains.

Findings

Finite polyyne chains undergo an insulator-metal transition under bias.

Non-equilibrium charging suppresses Peierls instability.

The proposed method can be applied to systems with effective single-particle Hamiltonians.

Abstract

A method for the study of the electronic transport in strongly coupled electron-phonon systems is formalized and applied to a model of polyyne chains biased through metallic Au leads. We derive a stationary non equilibrium polaronic theory in the general framework of a variational formulation. The numerical procedure we propose can be readily applied if the electron-phonon interaction in the device hamiltonian can be approximated as an effective single particle electron hamiltonian. Using this approach, we predict that finite polyyne chains should manifest an insulator-metal transition driven by the non-equilibrium charging which inhibits the Peierls instability characterizing the equilibrium state.