“…Cu(111) on sapphire provides an isolated and natural 2DES which exists as a surface state trapped between a Cu band gap along the [111] direction on the substrate side, and the insulating (vacuum or hBN) interface on the other side. Although hBN can be grown on other metals, such as Ir, , Rh, Ru, Cr, Fe, Ni, − Pd, , Pt, , we have chosen the Cu(111) system because of its demonstrated compatibility with wafer-scale technology and because its surface state is exceeding well characterized. The 2D electrons within this surface state have been used for a variety of fundamental experiments involving coherent quantum nanostructures and atom manipulation accessing quantum phase, quantum spin, and designer quantum materials .…”