Single-layer metallicity and interface magnetism of epitaxial graphene on SiC(000$\bar{1}$)

TL;DR

This study uses density functional theory to analyze the structural, electronic, and magnetic properties of epitaxial graphene on SiC(000$ar{1}$), revealing metallic behavior in the first layer and magnetic interface characteristics.

Contribution

It provides new insights into the metallicity and magnetic properties of epitaxial graphene on SiC(000$ar{1}$), highlighting differences from Si-face epitaxial films.

Findings

First graphene layer on C-face is purely metallic with preserved $ ext{π}$-bands.

Second graphene layer recovers free-standing characteristics.

Absence of Fermi-level pinning effects suggests potential for device applications.

Abstract

We perform density functional theory calculations for the determination of the structural and electronic properties of epitaxial graphene on 4H-SiC(000$\bar{1}$). Using commensurate supercells that minimize non-physical stresses we show that, in contrast with Si-face epitaxial films, the first graphene layer that forms on the C-face of SiC is purely metallic with its $\pi$-bands partially preserved. Typical free-standing characteristics are fully recovered with a second graphene layer. We moreover discuss on the magnetic properties of the interface and the absence of Fermi-level pinning effects that could allow for a plausible device operation starting from the off-state.