Symposium EQ20—Beyond Graphene 2D Materials—Synthesis, Properties and Device Applications

Ursula Wurstbauer, University of Münster

Light Matter Interaction and Quantum Confinement in 2D Polar Metals

Written by Don Monroe

Two-dimensional materials have attracted great interest, but most of them are semimetallic or semiconducting. Wurstbauer described the optical properties of atomically thin metallic layers created with “confinement heteroepitaxy” by co-author Robinson’s Group at Penn State. These “2D polar metals,” including Ga, In, Sn, and others, have a strong asymmetry driven by the imbalance between covalent bonding to the SiC substrate and van der Waals bonding to an overlying graphene layer.

Wurstbauer described ellipsometric characterization of these layers, which reveals quantum confinement effects in bilayers and trilayers, through comparison with theory from Quek’s group at the National University of Singapore. The experiments show two regions with the real part of the dielectric function near zero (ENZ). Wurstbauer is also pursuing low-temperature ellipsometry to better understand the superconducting transition in these layers.