Suppose there are two electrons per lattice site Will the sy

Suppose there are two electrons per lattice site. Will the system be a metal or an insulator and why?

Solution

Generallly most of compounds partially filled bands exhibit metallic properties.Few compounds shows insulating properties, this is becaause of electron-electron correlation. Example matt insulator (without considering interaction) into account) each site occupies two electrons whose spins are opposite , the lowe band occupies one electron and upper ocuupies another electron, such solid can behaves like metal.If each site occupies one electron, the upper band empty such solid behaves like a insulator.

Therefore, two electrons per lattice, system behaves like a metal.