Three independent groups have found the same type of superfast massless charge carriers in bulk sodium bismuthide and cadmium arsenide as give graphene its unusually large electrical and thermal conductivity.

Graphene is a semimetal (zero-gap semiconductor), meaning that there are very few charge carriers compared to a normal metal. While semimetals generally have far smaller electrical and thermal conductivity than metals, this is not the case in graphene, which has an intrinsic resistivity about two-thirds of the resistivity of silver.