654877bd_erials_Science_and_Engineering__Significance
[Date] 1927 [Candidate Moment] Arnold Sommerfeld applies quantum statistics to the Drude model of electrons in metals and develops the free-electron theory of metals. [Significance] 
Supplies a simple model for the behavior of electrons in a crystal structure of a metallic solid and contributes to the foundation of solid-state theory.
Greatest Moments in Materials Science and Engineering
Significance