semimetal

A semimetal is a material with a small overlap in the energy of the conduction band and valence bands.However, the bottom of the conduction band is typically situated in a different part of momentum space (at a different k-vector) than the top of the valence band. One could say that a semimetal is a semiconductor with a negative indirect bandgap. Schematically, the figure showsA) a semiconductor with a direct gap (like e.g. CuInSe2), B) a semiconductor with an indirect gap (like Si) and C) a semimetal (like Sn or graphite).
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(n.)
An element possessing metallic properties in an inferior degree and not malleable, as arsenic, antimony, bismuth, molybdenum, uranium, etc.
  

Compare with metal and nonmetal .An element with both metallic and nonmetallic properties. Examples are silicon, arsenic, and germanium.