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Resistance oscillations in two-dimensional electron systems induced by both ac and dc fields
W Zhang1, M A Zudov, L N Pfeiffer
1School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Physical Review Letters
|March 16, 2007
Summary
We observed that direct current (dc) fields significantly alter microwave photoresistance in two-dimensional electron systems. This interplay suggests coupled ac and dc effects, explained by indirect electron transitions.
Area of Science:
- Condensed matter physics
- Quantum transport phenomena
Background:
- Two-dimensional electron systems (2DES) exhibit unique quantum phenomena under external fields.
- Magnetotransport measurements probe electron behavior and scattering mechanisms.
Purpose of the Study:
- To investigate the influence of simultaneous alternating current (ac) and direct current (dc) fields on magnetotransport in a high-mobility 2DES.
- To understand the interplay between ac (microwave) and dc (Hall) excitations in photoresistance measurements.
Main Methods:
- Magnetotransport measurements were performed on a high-mobility two-dimensional electron system.
- The system was subjected to simultaneous microwave (ac) and Hall (dc) fields.
Main Results:
- Direct current excitation was found to nontrivially affect microwave photoresistance.
- Photoresistance maxima and minima shifted, indicating strong coupling between ac- and dc-induced effects.
- Observed quenching of microwave-induced zero resistance by a dc field was noted.
Conclusions:
- The observed phenomena are largely explained by indirect electron transitions under a combined resonant condition.
- A definitive link between observed quenching and a domain model requires further theoretical development.
- A unified theoretical framework for simultaneous ac and dc excitations is needed.
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