Bloch theorem

Bloch's theorem is a fundamental principle in solid-state physics that describes how electrons behave in periodic structures, like crystals. It states that in such materials, the wave functions of electrons can be expressed as a combination of plane waves and a periodic function, reflecting the symmetry of the crystal lattice. This means that the properties of electrons—such as their energy levels—are influenced by the repeating arrangement of atoms, leading to phenomena like electrical conductivity and the formation of energy bands. Essentially, it helps us understand how materials conduct electricity and shape their electronic properties.