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Published on: July 29, 2008
Conditions for dynamic localization in generalized ac electric fields
M M Dignam1, C Martijn de Sterke
1Department of Physics, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Physical Review Letters
|January 22, 2002
Summary
Dynamic localization of electrons in periodic potentials requires specific, discontinuous alternating current (AC) electric fields. Researchers found that only fields with sign changes can achieve exact dynamic localization, confirmed by simulations.
Area of Science:
- Condensed matter physics
- Quantum mechanics
- Solid-state physics
Background:
- Electrons in periodic potentials are fundamental to understanding solid-state materials.
- Alternating current (AC) electric fields can influence electron behavior, leading to phenomena like dynamic localization.
- Previous models often assumed continuous field variations, limiting understanding of localization conditions.
Purpose of the Study:
- To investigate the precise conditions for achieving dynamic localization of electrons in a periodic potential under an AC electric field.
- To identify the characteristics of AC electric fields that enable exact dynamic localization.
- To develop a general method for creating such localizing fields.
Main Methods:
- Utilized a general one-band model for electron behavior in periodic potentials.
- Developed a theoretical framework to analyze the effect of AC electric fields.
- Employed multiband simulations to numerically verify theoretical predictions.
Main Results:
- Established that only AC electric fields discontinuous at every sign change can induce exact dynamic localization.
- Derived a general procedure for constructing AC fields that lead to dynamic localization.
- Formulated an "area condition" that quantifies the requirements for these fields.
Conclusions:
- The nature of the AC electric field's discontinuity is critical for exact dynamic localization.
- The findings challenge previous assumptions and provide a new understanding of electron localization mechanisms.
- The derived area condition offers a practical criterion for designing experiments or materials exhibiting dynamic localization.
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