Origin of half-semimetallicity induced at interfaces of C-BN heterostructures

First-principles density functional calculations are performed in C-BN heterojunctions. It is shown that the magnetism of the edge states in zigzag shaped graphene strips and polarity effects in BN strips team up to give a spin asymmetric screening that induces half-semimetallicity at the interface, with a gap of at least a few tenths of eV for one spin orientation and a tiny gap of hundredths of eV for the other. The dependence with ribbon widths is discussed, showing that a range of ribbon widths is required to obtain half-semimetallicity. These results open new routes for tuning electronic properties at nanointerfaces and exploring new physical effects similar to those observed at oxide interfaces, in lower dimensions.