Complex microwave conductivity of Na-DNA powders

TL;DR

This study measures the complex microwave conductivity of Na-DNA powders across a temperature range, revealing intrinsic semiconductive behavior distinct from water molecule contributions.

Contribution

It provides the first detailed microwave conductivity measurements of Na-DNA powders, demonstrating their intrinsic semiconductive properties.

Findings

$\sigma_1$ is much larger than water contribution at room temperature

$\sigma_1$ decreases significantly with temperature

Na-DNA exhibits intrinsic semiconductive behavior

Abstract

We report the complex microwave conductivity, $\sigma=\sigma_1-i\sigma_2$, of Na-DNA powders, which was measured from 80 K to 300 K by using a microwave cavity perturbation technique. We found that the magnitude of $\sigma_1$ near room temperature was much larger than the contribution of the surrounding water molecules, and that the decrease of $\sigma_1$ with decreasing temperature was sufficiently stronger than that of the conduction of counterions. These results clearly suggest that the electrical conduction of Na-DNA is intrinsically semiconductive.