Journal Article

Atomically thin half-van der Waals metals enabled by confinement heteroepitaxy

Rotenberg, Eli, Koch, Roland J., Robinson, Joshua A., Shallenberger, Jeffrey, Zou, Qiang, Li, An-Ping, De La Fuente Duran, Ana, Bostwick, Aaron, Chang, Cui-Zu, Bersch, Brian, Jiang, Jue, van Duin, Adri C. T., Chuang, Ya-Wen, Wang, Yuanxi, Nayir, Nadire, Wang, Ke, Dong, Chengye, Briggs, Natalie, Subramanian, Shruti, Fu, Mingming, Jozwiak, Chris, Kolmer, Marek, Gai, Zheng, Ko, Wonhee, Zhu, Jun, Crespi, Vincent

2020

Overview

Atomically thin two-dimensional (2D) metals may be key ingredients in next-generation quantum and optoelectronic devices. However, 2D metals must be stabilized against environmental degradation and integrated into heterostructure devices at the wafer scale. The high-energy interface between silicon carbide and epitaxial graphene provides an intriguing framework for stabilizing a diverse range of 2D metals. Here we demonstrate large-area, environmentally stable, single-crystal 2D gallium, indium and tin that are stabilized at the interface of epitaxial graphene and silicon carbide. The 2D metals are covalently bonded to SiC below but present a non-bonded interface to the graphene overlayer; that is, they are ‘half van der Waals’ metals with strong internal gradients in bonding character. These non-centrosymmetric 2D metals offer compelling opportunities for superconducting devices, topological phenomena and advanced optoelectronic properties. For example, the reported 2D Ga is a superconductor that combines six strongly coupled Ga-derived electron pockets with a large nearly free-electron Fermi surface that closely approaches the Dirac points of the graphene overlayer. Single-crystal 2D metals are stabilized at the interface between epitaxial graphene and silicon carbide, with strong internal gradients in bonding character. The confined 2D metals demonstrate compelling superconducting properties.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Springer Nature - Nature Publishing Group
• Subject: 140/133 / 140/146 / 639/301/119/1003 / 639/301/357/1018 / Biomaterials / Bonding strength / Chemistry and Materials Science / Condensed Matter Physics / Environmental degradation / Epitaxy / Fermi surfaces / Free electrons / Gallium / Graphene / Heterostructures / MATERIALS SCIENCE / Metals / Nanotechnology / Optical and Electronic Materials / Optoelectronic devices / Silicon / Silicon carbide / Single crystals / Superconducting devices / Superconducting properties and materials / Superconductivity / Two-dimensional materials