Resistance oscillations in two-dimensional electron systems induced by both ac and dc fields.
We report on magnetotransport measurements in a high-mobility two-dimensional electron system subject simultaneously to ac (microwave) and dc (Hall) fields. We find that dc excitation affects microwave photoresistance in a nontrivial way. Photoresistance maxima (minima) evolve into minima (maxima) and back, reflecting strong coupling and interplay of ac- and dc-induced effects. Most of our observations can be explained in terms of indirect electron transitions using a new, combined resonant condition. Observed quenching of microwave-induced zero resistance by a dc field cannot be unambiguously linked to a domain model, at least before a systematic theory treating both excitation types within a single framework is developed.
Zhang
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W
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Zudov
M A
MA
Pfeiffer
L N
LN
West
K W
KW