Phase study of oscillatory resistances in microwave-irradiated- and dark-GaAs/AlGaAs devices: indications of a new class of the integral quantum Hall effect

Mani, R. G. ; Johnson, W. B. ; Umansky, V. ; Narayanamurti, V. ; Ploog, K. (2009) Phase study of oscillatory resistances in microwave-irradiated- and dark-GaAs/AlGaAs devices: indications of a new class of the integral quantum Hall effect Physical Review B, 79 (20). 205320_1-205320_10. ISSN 1098-0121

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Official URL: http://prb.aps.org/abstract/PRB/v79/i20/e205320

Related URL: http://dx.doi.org/10.1103/PhysRevB.79.205320

Abstract

We report the experimental results from a dark study and a photoexcited study of the high-mobility GaAs/AlGaAs system at large filling factors, v. At large v, the dark study indicates several distinct phase relations ("type 1," "type 2," and "type 3") between the oscillatory diagonal and Hall resistances, as the canonical integral quantum Hall effect (IQHE) is manifested in the type 1 case of approximately orthogonal diagonal and Hall resistance oscillations. Surprisingly, the investigation indicates quantum Hall plateaus also in the type 3 case characterized by approximately "antiphase" Hall and diagonal resistance oscillations, suggesting an unfamiliar and distinct class of IQHE. Transport studies under microwave photoexcitation exhibit radiation-induced magneto-resistance oscillations in both the diagonal, Rxx, and off-diagonal, Rxy, resistances. Further, when the radiation-induced magnetoresistance oscillations extend into the quantum Hall regime, there occurs a radiation-induced nonmonotonic variation in the amplitude of Shubnikov-de Haas (SdH) oscillations in Rxx vs B, and a nonmonotonic variation in the width of the quantum Hall plateaus in Rxy. The latter effect leads into the vanishing of IQHE at the minima of the radiation-induced Rxx oscillations with increased photoexcitation. We reason that the mechanism which is responsible for producing the nonmonotonic variation in the amplitude of SdH oscillations in Rxx under photoexcitation is also responsible for eliminating, under photoexcitation, the type 3 associated IQHE in the high-mobility specimen.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:30622
Deposited On:23 Dec 2010 13:02
Last Modified:17 May 2016 13:14

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