Carbon cage-like materials as potential low work function metallic compounds: Case of clathrates

TL;DR

This study explores C-46 clathrate materials, revealing their potential as low work function metals suitable for electron-emitting devices through ab-initio calculations and doping strategies.

Contribution

It introduces the possibility of turning C-46 clathrates into low work function metals via doping, a novel approach for such cage-like materials.

Findings

C-46 clathrate has small electronic affinity similar to diamond.

Doping with lithium can turn C-46 into a true metal with low work function.

Doped C-46 could be useful for electron-emitting devices.

Abstract

We present an ab-initio calculation of the electronic affinity of the hypothetical C-46 clathrate by studying its bare and hydrogenated (100) surfaces. We show that such a system shares with the diamond phase a small electronic affinity. Further, contrary to the diamond phase, the possibility of doping endohedrally these cage-like systems allows to significantly raise the position of the Fermi level, resulting in a true metal with a small work function. This is illustrated in the case of the Li8@C-46 doped compound. Such a class of materials might be of much interest for the design of electron-emitting devices.