An international team led by Miguel M. Ugeda (CIC nanoGUNE) and Michael F. Crommie (UC. Berkeley (USA)) has demonstrated the coexistence of superconductivity and charge density wave (CDW) order in a single layer of NbSe2, a model transition metal dichalcogenide (TMD) metal. The demonstration that a single layer of NbSe2 is a true 2D superconductor is a breakthrough in the field of 2D materials. Very few 2D superconductors exist in nature, and single-layer NbSe2 is the first among them that remains a superconductor in its isolated, 2D form without the need of a special substrate. Furthermore, CDW order - spatial modulation of both the electron density and the atomic lattice (see figure below) – has been revealed to be a genuine 2D electronic phenomenon in NbSe2. This work has been recently reported in Nature Physics.