Absolutely Small, Chapter 19: Metals, Insulators, and Semiconductors

This chapter uses the ideas of delocalized molecular orbitals to explain why metal conducts electricity and insulators donAÆt. The ideas are also used to explain what a semiconductor is. Semiconductors, particularly silicon, are the materials used to make all of our computers. The chapter goes on to describe why passing electricity through a metal, such as the heating element in an electric stove, makes it get hot, and why when it gets hot, it glows red. To do this, the concept of phonons, mechanical waves that move in solids is introduced. The scattering (collision) of electrons and phonons produce electrical resistance and heating of metals when electricity is passed through them. Based on the ideas of electron-phonon scattering, superconductivity is discussed.