Tuning Conductivity and Spin Dynamics in Few-Layer Graphene via In Situ Potassium Exposure

TL;DR

This study demonstrates how in situ potassium intercalation enhances the electrical conductivity and alters spin dynamics in few-layer graphene, revealing increased charge carriers and characteristic ESR signals.

Contribution

It provides a systematic analysis of potassium intercalation effects on conductivity and spin properties in few-layer graphene, using microwave conductivity and ESR measurements.

Findings

Conductivity increases by about an order of magnitude with potassium doping.

ESR shows two asymmetric Dysonian lines indicating mobile charge carriers.

Doping affects the ESR line width, especially in the broader component.

Abstract

Chemical modification, such as intercalation or doping of novel materials is of great importance for exploratory material science and applications in various fields of physics and chemistry. In the present work, we report the systematic intercalation of chemically exfoliated few-layer graphene with potassium while monitoring the sample resistance using microwave conductivity. We find that the conductivity of the samples increases by about an order of magnitude upon potassium exposure. The increased of number of charge carriers deduced from the ESR intensity also reflects this increment. The doped phases exhibit two asymmetric Dysonian lines in ESR, a usual sign of the presence of mobile charge carriers. The width of the broader component increases with the doping steps, however, the narrow components seem to have a constant line width.