Discovery of Cu3Pb

Materials discovery enables both realization and understanding of new, exotic, physical phenomena. An emerging approach to the discovery of novel phases is high‐pressure synthesis within diamond anvil cells, thereby enabling in situ monitoring of phase formation. Now, the discovery via high‐pressure synthesis of the first intermetallic compound in the Cu‐Pb system, Cu₃Pb is reported. Cu₃Pb is notably the first structurally characterized mid‐ to late‐first‐row transition‐metal plumbide. The structure of Cu₃Pb can be envisioned as a direct mixture of the two elemental lattices. From this new framework, we gain insight into the structure as a function of pressure and hypothesize that the high‐pressure polymorph of lead is a possible prerequisite for the formation of Cu₃Pb. Crucially, electronic structure computations reveal band crossings near the Fermi level, suggesting that chemically doped Cu₃Pb could be a topologically nontrivial material.     

Layered Black Phosphorus: Strongly Anisotropic Magnetic,Electronic, and Electron‐Transfer Properties

Layered elemental materials, such as black phosphorus, exhibit unique properties originating from their highly anisotropic layered structure. The results presented herein demonstrate an anomalous anisotropy for the electrical, magnetic, and electrochemical properties of black phosphorus. It is shown that heterogeneous electron transfer from black phosphorus to outer‐ and inner‐sphere molecular probes is highly anisotropic. The electron‐transfer rates differ at the basal and edge planes. These unusual properties were interpreted by means of calculations, manifesting the metallic character of the edge planes as compared to the semiconducting properties of the basal plane. This indicates that black phosphorus belongs to a group of materials known as topological insulators. Consequently, these effects render the magnetic properties highly anisotropic, as both diamagnetic and paramagnetic behavior can be observed depending on the orientation in the magnetic field.