A Landauer Formula for Bioelectronic Applications

TL;DR

This paper generalizes the Landauer formula to explain unconventional bioelectronic conductance phenomena observed in proteins, accounting for tunneling and decoherence effects, and simplifies predictions of transport properties using macroscopic parameters.

Contribution

It introduces a generalized Landauer formula that incorporates tunneling and decoherence, enabling simplified, predictive modeling of protein conductance without extensive microscopic details.

Findings

Explains temperature-independent conductance in proteins.

Accounts for distance-independent conductance within single proteins.

Provides a practical method to predict experimental outcomes using macroscopic parameters.

Abstract

Recent electronic transport experiments using metallic contacts attached to proteins identified some 'stylized facts' which contradict conventional wisdom that increasing either the spatial distance between the electrodes or the temperature suppresses conductance exponentially. These include nearly temperature independent conductance over the protein in the 30-300K range, distance independent conductance within a single-protein in the 1-10 nm range and an anomalously large conductance in the 0.1-10 nS range. In this paper we develop a generalization of the low temperature Landauer formula which can account for the joint effects of tunneling and decoherence and can explain these new experimental findings. We use novel approximations which greatly simplify the mathematical treatment and allow us to calculate the conductance in terms of a handful macroscopic parameters instead of the myriads of microscopic parameters describing the details of an atomic level quantum chemical computation. The new approach makes it possible to get predictions for the outcomes of new experiments without relying solely on high performance computing and can distinguish important and unimportant details of the protein structures from the point of view of transport properties.