Specific heat and magneto-thermal oscillations of two-dimensional electron gas in a magnetic field

Zawadzki, W.; Lassnig, R.

doi:10.1016/0038-1098(84)90324-7

Cited by 59 publications

(21 citation statements)

References 2 publications

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“…11͑a͒ shows theoretical values of C el Ϫ1 which are derived by assuming a Gaussian-type density of states with the level broadening parameter of 0.5 meV and a 5% constant background density of states. 35,36 The dotted line in Fig. 11͑b͒ indicates the values of Eq.…”

Section: A Mechanismmentioning

confidence: 99%

Highly sensitive and tunable detection of far-infrared radiation by quantum Hall devices

Kawano

Hisanaga

Takenouchi

et al. 2001

Journal of Applied Physics

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We studied far-infrared ͑FIR͒ response due to cyclotron resonance ͑CR͒ of two-dimensional electron gas systems in GaAs/AlGaAs heterostructures by using cyclotron radiation from n-InSb devices as the illumination source. We examined the dependence of the FIR response on different experimental parameters, including the aspect ratio of Hall bars, electron mobility, bias current, illumination intensity, magnetic field, and lattice temperature. A strong photoresponse emerges only in the vicinity of integer quantum Hall effect ͑IQHE͒ regimes. Time-resolved measurements show that the recombination lifetime of excited carriers depends largely on the electron mobility, ranging from 5 s to 1 ms at 4.2 K. The temporal decay of photoresponse is nonexponential in higher-mobility samples, whereas it is exponential with a single time constant in lower-mobility samples. This, together with the relatively large time constants, suggests that the FIR response is induced through multitrapping processes, in which excited carriers in Landau levels are repeatedly captured by localized states and reexcited to delocalized states. This multitrapping process is suggested to be promoted by the CR-induced heating of the electron system. Theoretical calculation based on the electron heating model reasonably reproduces characteristic dependence of the photoresponse on the magnetic field in the vicinity of IQHE plateaus. The IQHE Hall bars serve as a high-sensitive narrow-band FIR detector, where the highest sensitivity reaches ϳ10 8 V/W. Tunability of the detector is demonstrated by varying the electron density. We discuss briefly the design of high-sensitive FIR detectors using the IQHE Hall bars.

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Section: A Mechanismmentioning

confidence: 99%

Highly sensitive and tunable detection of far-infrared radiation by quantum Hall devices

Kawano

Hisanaga

Takenouchi

et al. 2001

Journal of Applied Physics

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“…A constant heat input AQ is applied to the sample resulting in a temperature increase AT, which has to be determined from the following equation: A0 = |a[(r+AD 4 -r 4 ] + c el (7;^r)Ar (5) with C lat = «r 3 = 6.21xl0 16 A:r 3 (cm" 3 ) and 0 D = 344 K. 9 The difference between C el (r + AD and C el (7) is neglected, since the temperature dependence of C el is weak for the kT/T values considered (between 0.15 and0.25). 2 The calculated AT(B) functions for the different densities of states are plotted in Figs. 1 and 2.…”

Section: Filling Factormentioning

confidence: 99%

“…The interpretation of the spikes at lower magnetic fields as inter-Landau-level contributions is confirmed through their temperature dependence: The inter-Landau-level contributions are only present at higher temperatures, in agreement with the theoretical prediction. 2 From these data we can in principle determine the form of the density of states. We have therefore performed calculations of the electronic specific heat C el according to Ref.…”

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confidence: 99%

Specific Heat of Two-Dimensional Electrons in GaAs-GaAlAs Multilayers

et al. 1985

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We report the first observation of the magnetic-field-dependent electronic specific heat in GaAs-GaAs multilayers. With a heat-pulse technique oscillations of the sample temperature on the order of millikelvins were observed. Both intra-and inter-Landau-level contributions could be distinguished. Theoretical fits to the data reveal a density of states consisting of Gaussian peaks on a flat background.

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“…In the last years, thermodynamics of two-dimensional electron gas (2DEG) in thin films has been quite intensively studied [1][2][3][4]. Thermodynamic characteristics of the films are dependent not only on the film thickness but also on profile and parameters of quantum well (QW).…”

Section: Introductionmentioning

confidence: 99%