Synthesis of Air-Stable, Atomically Thin Heavy Metals through Confinement Heteroepitaxy*

Atomically thin heavy metals (Pb, Bi) are known to exhibit strong Rashba spin orbit coupling suggesting their viability in spintronics; however, their instability in ambient precludes device integration. We demonstrate the synthesis of centimeter-scale, two-dimensional Pb, Bi, and PbGa via confinement heteroepitaxy (CHet) which leverages the interface between epitaxial graphene and silicon carbide to assemble atomically thin, air-stable 2D metals. Through ex-situ microscopy, spectroscopy, diffraction, and transport characterization of these 2D heavy metals, we find > 90% 2D-metal coverage, unique spectroscopic features in Raman, evidence of ~500meV spin splitting in 2D-Pb, and superconductivity up to 3K in 2D-PbGa.