Weak localization and antilocalization in semiconducting polymer sandwich devices

TL;DR

This study investigates magnetoresistance effects in polyfluorene devices, revealing weak localization and antilocalization phenomena influenced by voltage, temperature, and electric field, with implications for understanding charge transport in semiconducting polymers.

Contribution

It provides experimental evidence of weak localization and antilocalization in semiconducting polymer devices and analyzes their dependence on various parameters using weak localization theory.

Findings

Negative or positive magnetoresistance observed depending on voltage

Phase-breaking length remains large even at room temperature

Spin-orbit interaction varies with applied electric field

Abstract

We have performed magnetoresistance measurements on polyfluorene sandwich devices in weak magnetic fields as a function of applied voltage, device temperature (10K to 300K), film thickness and electrode materials. We observed either negative or positive magnetoresistance, dependent mostly on the applied voltage, with a typical magnitude of several percent. The shape of the magnetoresistance curve is characteristic of weak localization and antilocalization. Using weak localization theory, we find that the phase-breaking length is relatively large even at room temperature, and spin-orbit interaction is a function of the applied electric field.