Condensed matter physics, originally called solid-state physics, involves the properties of bulk substances, such as a lump of silicon, as opposed to those of individual atoms. The field has blossomed in the last two decades with the advent of new materials with special properties, such as better photovoltaic cells and ever smaller memories for computers.
But the field was created by researchers like Seitz.
In the early 1930s, while he was a graduate student at Princeton University, Seitz and his mentor Eugene P. Wigner were the first to calculate the physical properties of bulk sodium based on the known properties of sodium ions.
Their technique, known as the Wigner-Seitz method, was later used by other researchers to calculate the energies of the so-called band gaps that electrons jump over to conduct a current in semiconductors — the basis of the transistor — and is considered the catalyst for the formation of solid-state physics in the United States.
In 1940, Seitz published the seminal text “The Modern Theory of Solids,” which was the bible of the field for many years, according to Cohen.
Seitz’s subsequent research involved the theory and properties of crystals and the diffusion of atoms into crystalline structures.