OREANDA-NEWS Atomically thin superconductors are desirable in miniature devices but also of much interest to scientists because they can be used to test ideas about the limits of the existence of superconductivity.

Bulk materials often become superconducting if a sufficient amount of electrons is added and they start to strongly interact with each other.

Superconductivity in one atom thick two-dimensional materials was discovered only a decade ago but the findings often referred not to isolated atomically thin layers but their bulk assemblies and the evidence was so far weak and sometimes controversial.

In a report published in Nature Communications, scientists used a process called intercalation – essentially coating phosphorene layers in black phosphorus with different alkali atoms that donate their electrons to phosphorene. In each case this turned black phosphorus into a superconductor with exactly the same properties, irrespective of what kinds of atoms were used to add electrons to the layers of phosphorene.

Prof Irina Grigorieva said: “Nothing like this was known before. This new understanding is important for developing atomically thin materials towards applications in electronics and quantum technologies.”

Renyan Zhang, a PhD student who led the experimental effort, said: “Phosphorene and its parent material, black phosphorus, are in many respects similar to graphene and graphite.

"We expected that each electron-donating metal will produce a different superconductor, as is the case with graphene and graphite. But to our great surprise all metal donors produced exactly the same superconducting material, with identical properties.”