Surface state 2026-10-18
A surface state is an electronic state localized near a material boundary. Its occupation can store electric charge and change the near-surface electric potential, producing band bending.
Walter Houser Brattain's surface studies combined changes of contact potential under light, electrical conductivity, and transient response to distinguish surface effects from bulk properties. His Nobel lecture distinguishes fast and slow charge responses and warns that slow behavior can involve the surrounding gas rather than a simple electronic state.[ref]