Seventy years ago the founders of quantum mechanics were still around and working to see what all of the new math meant. Among them was Paul Dirac who constructed the atomic collapse theory that describes some interesting electron behavior in the presence of a super-heavy nucleus. For decades testing the theory has proven to be extremely difficult, but researchers at Berkeley Lab have successfully applied the unique properties of graphene to construct a similar system.
Thanks to the high speeds electrons can move at on a sheet of graphene, the researchers were able to construct an artificial atom by packing positively charged impurities close to each other within the graphene. Once the impurities, calcium atoms specifically, passed the critical density, electrons changed their flow around the atoms greatly. Instead of following a circular orbit like in a Bohr diagram, the electrons swung in, very near the nucleus, before spiraling back out. If this happened within a real atom, the system would emit a positron as the electron escapes the nucleus, but in graphene it was instead a positively charged hole that was created.
While the physics may seem too exotic to be important, this could actually impact the use of graphene in future electronics as impurities will be used to create special effects. The ability to affect electron paths and generate positive holes like this could be made useful at some point.
Source: Berkeley Lab