Magnetic-field-dependent self-consistent electronic structure of an inversion layer in the two-subband state

Trott, S.; Paasch, G.; Gobsch, G.; Trott, M.

doi:10.1103/physrevb.39.10232

Cited by 15 publications

(8 citation statements)

References 9 publications

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“…As pointed out in Ref. 29, when only a small number of quantized LLs belonging to two different subbands are occupied, the distribution of electrons between these levels does not necessarily match the B = 0 subband densities. This leads to a mismatch between the total electron charge density distributions at B = 0 and high B.…”

Section: -20mentioning

confidence: 93%

Stability of theq/3fractional quantum Hall states

2011

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Magneto-transport measurements in a wide GaAs quantum well in which we can tune the Fermi energy (EF ) to lie in different Landau levels of the two occupied electric subbands reveal a remarkable pattern for the appearance and disappearance of fractional quantum Hall states at ν = 10/3, 11/3, 13/3, 14/3, 16/3, and 17/3. The data provide direct evidence that the q/3 states are stable and strong even at such high fillings as long as EF lies in a ground-state (N = 0) Landau level of either of the two electric subbands, regardless of whether that level belongs to the symmetric or the anti-symmetric subband. Evidently, the node in the out-of-plane direction of the anti-symmetric subband does not de-stabilize the q/3 fractional states. On the other hand, when EF lies in an excited (N > 0) Landau level of either subband, the wavefunction node(s) in the in-plane direction weaken or completely de-stabilize the q/3 fractional quantum Hall states. Our data also reveal that the strength of the q/3 fractional states near the crossing of two Landau levels belonging to the two subbands depends on the relative spin polarization of the levels; specifically, the states remain stable very near the crossing if the two levels have parallel spins.2

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Section: -20mentioning

confidence: 93%

Stability of theq/3fractional quantum Hall states

2011

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“…We remark that while LL pinning in two-subband systems is a general phenomenon [22], its manifestation is more pronounced in bilayerlike electron systems with asymmetric (imbalanced) charge distributions [23]. For example, we do not see signatures of LL pinning in the data of Fig.…”

mentioning

confidence: 87%

“…As pointed out in Ref. [22], when only a small number of quantized LLs belonging to two different subbands are occupied, the distribution of electrons between these levels does not necessarily match the B ¼ 0 subband densities. This leads to a mismatch between the total electron charge density distributions at B ¼ 0 and high B, which is given by…”

mentioning

confidence: 94%

“…This leads to a mismatch between the total electron charge density distributions at B = 0 and high B. The pinning and the inter-LL charge transfer help bring these distributions closer to each other [22,23]. To demonstrate such a pinning quantitatively and determine the boundary inside which the S1↑ and A0↓ levels are pinned together, we performed self-consistent calculations of the potential energy and charge distribution at high B, similar to those described in Ref.…”

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confidence: 99%

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Evolution of the7/2Fractional Quantum Hall State in Two-Subband Systems

et al. 2011

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We report the evolution of the fractional quantum Hall state (FQHS) at a total Landau level (LL) filling factor of ν=7/2 in wide GaAs quantum wells in which electrons occupy two electric subbands. The data reveal subtle and distinct evolutions as a function of density, magnetic field tilt angle, or symmetry of the charge distribution. At intermediate tilt angles, for example, we observe a strengthening of the ν=7/2 FQHS. Moreover, in a well with asymmetric change distribution, there is a developing FQHS when the LL filling factor of the symmetric subband ν(S) equals 5/2 while the antisymmetric subband has a filling factor of 1<ν(A)<2.

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“…Since the occupation of the two subbands depends on the magnetic field that quantizes the DOS into Landau levels, and since the shape of the confining potential, the intersubband spacing, and the spacial charge distribution are interdependent, the Schrödinger and Poisson equations have to be solved self-consistently for each value of the magnetic field. 20,21 In our model we keep the electron density fixed and assume a Gaussian broadened DOS with a width that increases with the square root of the magnetic field. As the ͑bare͒ spin splitting is too small to have an effect, it is neglected in the calculations.…”

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confidence: 99%

Magnetization of a two-dimensional electron gas with a second filled subband

et al. 2003

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We have measured the magnetization of a dual-subband two-dimensional electron gas, confined in a GaAs/ AlGaAs heterojunction. In contrast to two-dimensional electron gases with a single subband, we observe non-1/B-periodic, triangularly shaped oscillations of the magnetization with an amplitude significantly less than 1 B * per electron. All three effects are explained by a field-dependent self-consistent model, demonstrating that the shape of the magnetization is dominated by oscillations in the confining potential. Additionally, at 1 K, we observe small oscillations at magnetic fields where Landau levels of the two different subbands cross. When an extra degree of freedom is added to a twodimensional electron gas ͑2DEG͒, many-body interactions can lead to the formation of novel electronic grounds state at the crossings of the different energy levels in the system.

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Magnetic-field-dependent self-consistent electronic structure of an inversion layer in the two-subband state

Cited by 15 publications

References 9 publications

Stability of theq/3fractional quantum Hall states

Stability of theq/3fractional quantum Hall states

Evolution of the7/2Fractional Quantum Hall State in Two-Subband Systems

Magnetization of a two-dimensional electron gas with a second filled subband

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