Graphene triangles with an edge length of just a few atoms behave like quantum magnets. When two of these nano-triangles are connected, a "quantum entanglement" of their magnetic moments takes place: The structure becomes antiferromagnetic. This could be a breakthrough for future magnetic materials and a further step towards spintronics.
Graphene has numerous outstanding properties. Last year, a team of Empa researchers was able to show that it can even be magnetic: They succeeded in synthesizing a molecule in the shape of a tuxedo fly that has special magnetic properties. In the last three years, several teams, including the Empa team, have also succeeded in producing so-called triangulenes, which consist of only a few dozen carbon atoms, by means of chemical syntheses in an ultra-high vacuum. If two of these are connected to each other via a single carbon-carbon bond (so-called triangulene dimers), not only is their magnetism retained; their magnetic moments should also form a "quantum entangled" state. This means that the spin, or torque, of their unpaired electrons should point in opposite directions. This state is known as the antiferromamagnetic (or spin-0) state.
In addition, the theory also predicted that it should be possible to excite the triangulene dimers into a state in which their spins are no longer perfectly aligned (spin-1 state).
