Bottom-up growth of monolayer honeycomb SiC

TL;DR

This paper reports the successful bottom-up synthesis of large-area, monocrystalline monolayer honeycomb SiC, revealing its stability and unique electronic properties, paving the way for diverse technological applications.

Contribution

It demonstrates the first epitaxial growth of stable, monolayer honeycomb SiC on transition metal carbide substrates with tunable electronic features.

Findings

Monolayer honeycomb SiC can be synthesized epitaxially on transition metal carbide films.

The 2D SiC is nearly planar and stable up to 1200°C in vacuum.

Electronic structure shows a Dirac-like feature, with strong spin-splitting on TaC substrate.

Abstract

The long theorized two-dimensional allotrope of SiC has remained elusive amid the exploration of graphenelike honeycomb structured monolayers. It is anticipated to possess a large direct band gap (2.5 eV), ambient stability, and chemical versatility. While $sp^{2}$ bonding between silicon and carbon is energetically favorable, only disordered nanoflakes have been reported to date. Here we demonstrate large-area, bottom-up synthesis of monocrystalline, epitaxial monolayer honeycomb SiC atop ultrathin transition metal carbide films on SiC substrates. We find the 2D phase of SiC to be almost planar and stable at high temperatures, up to 1200{\deg}C in vacuum. Interactions between the 2D-SiC and the transition metal carbide surface result in a Dirac-like feature in the electronic band structure, which in the case of a TaC substrate is strongly spin-split. Our findings represent the first step towards routine and tailored synthesis of 2D-SiC monolayers, and this novel heteroepitaxial system may find diverse applications ranging from photovoltaics to topological superconductivity.