Adsorption-Free Growth of Ultra-Thin Molybdenum Membranes with a Low-Symmetry Rectangular Lattice Structure.

Although low-symmetry lattice structure of 2D transition metals is highly anticipated for both fundamental research and potentially distinctive application, it still has not been experimentally realized, which greatly hinders the exploration of the unique properties. Here, ultra-thin body-centered-cubic (bcc) phase molybdenum (Mo) membranes are successfully synthesized with a low-symmetry rectangular (110) crystal face via an adsorption-free reaction. Through experimental and density functional theory studies, no foreign atoms being adsorbed is shown to be a key factor for the successful preparation of the bcc phase 2D transition metal with (110) faces. The realization of 2D Mo(110) with a low-symmetric rectangular lattice structure extends the scope of 2D structures and is also beneficial for the exploration and development of low-symmetry rectangular lattice-structured materials with unique properties.