Understanding the Microscopic Mechanisms Associated with Conductivity in Cytochrome Wires from First-Principles Modeling

To develop new biologically-inspired materials for electronics, we need to understand the microscopic mechanisms associated with carrier conductivity. Such an understanding is hindered by the structural and chemical complexity of these systems. Here, we present theoretical studies of conductivity within microbial cytochrome wires, which exhibit carrier conduction over microns. We introduce an approach to extract charge carrier site information directly from Kohn-Sham density functional theory (DFT), providing input to a quantum charge carrier model that includes both coherent charge transport and the impact of decoherence. We demonstrate that molecular fluctuations strongly impact electron carrier diffusion lengths; specifically, both non-instantaneous decoherence and non-perturbative dynamic disorder allow the system to more easily overcome static site energy barriers, improving conductivity within certain parameter regimes. These studies provide insights into molecular and electronic determinants of long-range electronic conductivity in microbial cytochrome wires and highlight design principles for bioinspired, heme-based conductive materials.<br/><br/>This research was primarily supported by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967).