0 a chemical element with some of the properties of a metal and some of a non-metal, for example silicon and arsenic
Metalloids are sometimes called semimetals, a practice that has been discouraged as the term "semimetal" has a different meaning in physics than in chemistry.
Physically, they are shiny, brittle solids with intermediate to relatively good electrical conductivity and the electronic band structure of a semimetal or semiconductor.
In physics, a semimetal is an element or a compound in which the valence band marginally (rather than substantially) overlaps the conduction band.
Like a metal, the conductivity of graphite in the direction of its planes decreases as the temperature is raised; it has the electronic band structure of a semimetal.
With nanowire arrays, it is possible to exploit semimetal-semiconductor transition due to the quantum confinement and use materials that normally would not be good thermoelectric materials in bulk form.
