PowerPoint Presentation

Microwave Radiation-Induced Magnetoresistance Oscillations in high mobility GaAs/AlGaAs system under Bichromatic excitation

Presented By : Binuka GunawardanaAdvisor : Dr. Ramesh G. Mani

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ContentIntroduction2D Electron Systems (2DES)Landau Levels (LL)Quantum Hall EffectShubnikov de Hass (SdH) OscillationsMicrowave Induced Magnetoresistance Oscillations (MIMOs) Theoretical BackgroundMotivationExperimental setupResultsDiscussionSummary

2D Electron systemAllowed quantized energy levels limits Z-direction motion2D Electron system (2DES)

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Ref: http://dx.doi.org/10.18419/opus-6695

Landau Levels (LLs)

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Integer Quantum Hall Effect (IQHE)

Degenerated LLFilling factor

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Ref: Nobel Lecture by Klaus von Klitzing, 1985

QHE and Shubnikov de Hass(SdH) Oscillations

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Ref: http://dx.doi.org/10.18419/opus-6695

Microwave Induced Magnetoresistance Oscillations (MIMOs)

IQHE

SdH

Ref: R. G. Mani,Nature (London) 420, 646 (2002)MIMOs

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Ref: R. G. Mani,Nature (London) 420, 646 (2002)

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Theoretical Background of MIMOs

Ref: A. C. Durst, S.Sachdev, N. Read, and S. M. Girvin, Phys.Rev.Lett. 91, 086803 (2003).Displacement Model7

Inelastic Model

Ref: I. A. Dmitriev, M. G. Vavilov, I. L. Aleiner, A. D. Mirlin, and D. G. Polyakov, Phys. Rev. B 71, 115316 (2005).8

Radiation Driven Electron Orbital Model

Ref: J. Inarrea and G. Platero, Phys. Rev. Lett. 94, 016806 (2005).9

Classical Memory Effect

Ref: Y. M. Beltukov and M. I. Dyakonov, Phys. Rev. Lett. 116, 176801 (2016).10

MIMOS Depends on what parameters?

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Motivation

Previous StudiesRef: M. A. Zudov, R. R. Du, L. N. Pfeier, and K. W. West, Phys. Rev. Lett. 96,236804 (2006).Obeys an Average of two Monochromatic resultsStrongly suppressed at zero resistance states (ZRS)12

Binuka Gunawardana (BG) - Binuka Gunawardana (BG) - Experimental Setup

Bichromatic Microwave Induced Magnetoresistance OscillationBichromatic MIMO13

Results : Comparing with Average

This figure shows the Rxx vs. 1/B for monochromatic excitation at 90.6 GHz48.7 GHz bichromatic excitation90.6 GHz & 48.7 GHz and the numerical arithmetic average of the monochromatic signals at 90.6 GHz & 48.7 GHz

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MIMOs for 90.6 GHz 48.7 GHz bichromatic MIMOs for90.6 GHz +48.7 GHzat same Microwave powers

Results : bMIMO behavior15

MIMOs for 90.6 GHz 41.0 GHz bichromatic MIMOs for90.6 GHz +41.0 GHzat same Microwave powers

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Results : Power dependence of bMIMOs

bMIMOs for frequency pair 90.6 GHz and 41.0 GHz for microwave power 4, 2, 1, 0.5 and 0.25 mW at the lower frequency, and constant power at the higher frequency (90.6 GHz) 18

The variation in the diagonal resistance, Rxx, with the change in the microwave power of the low frequency component under bichromatic photo-excitation conditions for (a) region (1), (b) region (2) and (c) region (3)19

nn+1n+2n+3n+4n+5n+6

B1

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nn+1

B2n+2n+3n+4n+5n+6

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n+3n+2n+1

nn+4n+5

B3n+6

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SummaryBichromatic response may not be a superposition or average of two monochromatic MIMO responsesThe amplitude of the bichromatic MIMO has a non linear relationship with MW powerAt low magnetic field bichromatic MIMO response is similar to low frequency response, when going to high magnetic field they both contributes and bichromatic MIMO response goes towards high frequency responseThe model developed can be used to explain the behavior of the bichromatic MIMO responses

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AcknowledgementStudy more about bichromatic MIMO dependency with MW propertiesFuture WorkSupervisor :Group Members:Funding AgenciesProf. Ramesh ManiDr. Annika KrissaHan Chun LiuCommittee Members:Zhuo WangProf. Unil PereraRasanga SamaraweeraUS Department of EnergyDE-SC001762Prof. Yohannes AbateRasadi MunasingheProf. Alexander KozhanovTharanga NanayakkaraProf. Russel WhiteKushan WijewardanaSajith WijayarathneRupesh GhimireArmy Research OfficeW911NF-10-1-0450

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SummaryBichromatic response may not be a superposition or average of two monochromatic MIMO responsesThe amplitude of the bichromatic MIMO has a non linear relationship with MW powerAt low magnetic field bichromatic MIMO response is similar to low frequency response, when going to high magnetic field they both contributes and bichromatic MIMO response goes towards high frequency responseThe model developed can be used to explain the behavior of the bichromatic MIMO responsesStudy more about bichromatic MIMO dependency with MW propertiesFuture Work

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