Spin effects in the magnetodrag between double quantum wells

Lok, J. G. S.; Kraus, S.; Pohlt, M.; Dietsche, W.; Klitzing, K. von; Wegscheider, Werner; Bichler, Max

doi:10.1103/physrevb.63.041305

Cited by 24 publications

(30 citation statements)

References 21 publications

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“…Compared to a single layer of the two-dimensional electron or hole system (2DES or 2DHS), the existence of another layer introduces significant interaction effects between two quantum wells. Over the years, many novel physical phenomena have been observed 2,3,4,5,6,7,8,9,10 . In addition, since the distance (or the coupling) between the two quantum wells can be controllably tuned from a few tenths of nanometer to several microns, DQW structures have shown promise as possible future electronic devices for next generation information processing 11 .…”

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confidence: 99%

Hysteresis in the quantum Hall regimes in electron double quantum well structures

2005

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We present in this paper experimental results on the transport hysteresis in electron double quantum well structures. Exploring the measurement technique of fixing the magnetic field and sweeping a front gate voltage (Vg), we are able to study the hysteresis by varying the top layer Landau level fillings while maintaining a relatively constant filling factor in the bottom layer, allowing us to tackle the question of the sign of Rxx(up)-Rxx(down), where Rxx(up) is the magnetoresistance when Vg is swept up and Rxx(down) when Vg swept down. Furthermore, we observe that hysteresis is generally stronger in the even integer quantum Hall effect (IQHE) regime than in the odd-IQHE regime. This, we argue, is due to a larger energy gap for an even-IQHE state, determined by the Landau level separation, than that for an odd-IQHE state, determined by the Zeeman splitting.There is a great deal of current interest in the study of the double quantum well (DQW) structures 1 . Compared to a single layer of the two-dimensional electron or hole system (2DES or 2DHS), the existence of another layer introduces significant interaction effects between two quantum wells. Over the years, many novel physical phenomena have been observed 2,3,4,5,6,7,8,9,10 . In addition, since the distance (or the coupling) between the two quantum wells can be controllably tuned from a few tenths of nanometer to several microns, DQW structures have shown promise as possible future electronic devices for next generation information processing 11 .Recently, a new phenomenon has been discovered in the DQW structures: electronic transport hysteresis 12,13 . It was observed that, when the densities of two wells are different and tunneling is negligible, the magnetotransport coefficients show hysteretic behavior when the magnetic (B) field is swept up and down. This hysteretic behavior occurs when only one QW is in the integer quantum Hall effect (IQHE) regime, and is believed to be due to a spontaneous charge transfer between the two layers 12 . Specifically, when one layer enters into an IQHE state, its Fermi level jumps from one Landau level to another. Consequently, the chemical potential between the two QW's becomes unbalanced. In reaching an equilibrium state, a spontaneous charge transfer from one QW to the other will occur, via the ohmic contacts. Since one QW is in the IQHE regime where the bulk is insulating, redistribution of the transferred charges takes a finite time to reach completion. This finite time constant, combined with the finite sweeping rate of the B field, gives rise to a hysteresis in electronic transport.This hysteretic electronic transport was first observed in a single, high electron mobility quantum well with a low mobility parallel conducting channel 12 , and later in hole DQW structures 13 . So far, no studies have been conducted in the most common DQW structures, the electron DQW's. Thus, questions remain whether the hysteresis is universal and occurs in electron DQW's.In this paper, we present experimental results of the transpor...

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confidence: 99%

Hysteresis in the quantum Hall regimes in electron double quantum well structures

2005

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“…The critical test of the theory was performed in a recent experiment by Lok et al [45], which confirms that the transresistivity does not show the predicted double peak structure for the spin split Landau levels and the double-peak structure at higher filling factors is not caused by the screening effect [43].…”

Section: Introductionmentioning

confidence: 91%

“…Also, the response of composite fermions to large wave vector scattering has been studied through phonon magnetodrag measurements [44]. In addition, recent measurements reveal a new regime of the magnetodrag in a coupled 2DES at mismatched densities n 1 = n 2 in which the polarity of the drag voltage is opposite that normally found for electron systems [42,45]. Theoretical investigations were mostly carried out with incorporating the direct Coulomb mechanism [46,47,48,49].…”

Section: Introductionmentioning

confidence: 99%

Frictional magnetodrag between spatially separated two-dimensional electron systems: Coulomb versus phonon mediated electron–electron interaction

Badalyan

Kim

2003

Solid State Communications

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We study the frictional drag due to Coulomb and phonon mediated electron-electron interaction in a double layer electron system exposed to a perpendicular magnetic field. Within the random phase approximation we calculate the dispersion relation of the intra Landau level magnetoplasmons at finite temperatures and distinguish their contribution to the magnetodrag. We calculate the transresistivity ρ Drag as a function of magnetic field B, temperature T , and interlayer spacing Λ for a matched electron density. For Λ = 200 nm we find that ρ Drag is solely due to phonon exchange and shows no double-peak structure as a function of B. For Λ = 30 nm, ρ Drag shows the double-peak structure and is mainly due to Coulomb interaction. The value of ρ Drag is about 0.3 Ω at T = 2 K and for the half-filled second Lanadau level, which is about 13 times larger than the

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“…For instance, under certain circumstances, the diagonal terms in the magnetotransresistivity ( 21 xx and 21 yy ) has been observed to reverse sign when the chemical potential is changed in one layer while being kept fixed in the other. 20 This sign reversal with changing chemical potential ͑which incidentally has not been observed at Bϭ0) cannot be obtained from magnetodrag calculations using the self-consistent Born approximation, 21,22 and despite recent theoretical progress, 23 a fully satisfactory explanation of this phenomenon is not yet available.…”

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Sign reversal of drag in bilayer systems with in-plane periodic potential modulation

Alkauskas

Flensberg

et al. 2002

Phys. Rev. B

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We develop a theory for describing frictional drag in bilayer systems with in-plane periodic potential modulations, and use it to investigate the drag between bilayer systems in which one of the layers is modulated in one direction. At low temperatures, as the density of carriers in the modulated layer is changed, we show that the transresistivity component in the direction of modulation can change its sign. We also give a physical explanation for this behavior.

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Spin effects in the magnetodrag between double quantum wells

Cited by 24 publications

References 21 publications

Hysteresis in the quantum Hall regimes in electron double quantum well structures

Hysteresis in the quantum Hall regimes in electron double quantum well structures

Frictional magnetodrag between spatially separated two-dimensional electron systems: Coulomb versus phonon mediated electron–electron interaction

Sign reversal of drag in bilayer systems with in-plane periodic potential modulation

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