Superconductivity in doped picene

Studying carbon, with its many allotropes and compounds, is one of the most fascinating problems in science. To mention only physics, before graphene, which was awarded the Nobel prize in 2010 opening exciting perspectives for fundamental and applied research, many other systems, such as nanotubes, fullerenes and intercalated graphites have played an important role in several fields, including superconductivity. The most recent discovery is a new class of aromatic superconductors, comprising molecular crystals doped with alkali or alkaline earths. These are polycyclic aromatic hydrocarbons, i.e. planar molecules formed by a number of juxtaposed hexagonal benzene rings (C6H6). The first report of superconductivity regarded picene doped with potassium (K) and rubidium (Rb), with a maximum critical temperature (Tc) of 18 K; after that, superconductivity was also found in phenanthrene and coronene doped with K (Tc=5K and 15 K), phenanthrene doped with strontium (Sr) and barium (Ba) (Tc=5.6-5.8 K) and 1,2:8,9-dibenzopentacene C30H18 (Tc=33 K) doped with K.[1]