Semimetal

material with a very small overlap between the bottom of the conduction band and the top of the valence band

In physics, a semimetal is a material that has a small overlap between the valence and conduction bands, the highest energy levels where electrons are found and the lowest energy levels where holes are found.

Unlike metals, there is still some separation between the valence and conduction bands, but the small overlap still allows it to conduct electricity.