Electronic transport properties of graphene with 5 \textit{d} metal adatoms

Electronic transport properties of graphene are highly sensitive to adsorbates on its surface. Adsorbates can affect graphene through doping and scattering, and 5$d$ metal adsorbates have been predicted to induce strong spin-orbit coupling and open a bandgap [1]. Here we study the\textit{ in-situ} transport properties of single-layer graphene doped with 5$d$ heavy metal atoms. Iridium was deposited on graphene at a substrate temperature of 7 K under ultra-high vacuum condition. Gate-dependent conductivity measurements show that the mobility and minimum conductivity of graphene decrease with increasing Iridium concentration. The results are in agreement with the self-consistent theory of graphene with random charged impurities [2], and do not indicate any significant bandgap in graphene with Iridium adatoms. We will also discuss temperature-dependent measurements, and co-adsorption of Iridium and krypton.\\[4pt] [1] Phys. Rev. Lett. \textbf{109}, 266801 (2012)\\[0pt] [2] \textit{PNAS} \textbf{104}, 18392 (2007)