title: Conditions for dynamic localization in generalized ac electric fields.
abstract: We examine the conditions for dynamic localization of electrons in a periodic potential due to an applied ac electric field. Using a general one-band model, we establish the surprising result that only electric fields that are discontinuous at all changes of sign can lead to exact dynamic localization. We also develop a general procedure for constructing ac fields that yield dynamic localization and derive an "area condition" for such fields. We confirm this result numerically in a multiband simulation.
authors.affiliation: Department of Physics, Queen's University, Kingston, Ontario, Canada K7L 3N6.
authors.forename: M M
authors.initials: MM
authors.lastname: Dignam
authors.forename: C Martijn
authors.initials: CM
authors.lastname: de Sterke