Inter-subband scattering in a 2D electron gas

Coleridge, P. T.

doi:10.1088/0268-1242/5/9/006

Cited by 131 publications

(107 citation statements)

References 8 publications

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“…The small Dingle ratio of the shallower device implies that the charge centers are in such close proximity to the 2DEG that they induce large angle scattering. Dingle rations calculated using the amplitude growth of the SdH oscillations (R xx ∝ e −π/τ q ω c ) 18 shows good agreement with the ratios calculated from the onset of the SdH oscillations, as shown in Table I.…”

Section: Deg Depthsupporting

confidence: 77%

“…A common approach to experimentally determine the dominant scattering mechanisms in two-dimensional systems is to extract the power-law exponent from the density dependence of the mobility. Several experimental and theoretical studies have used similar techniques to analyze disorder in GaAs/AlGaAs structures, [15][16][17][18][19][20][21] Si MOSFETs, 22 and doped 4,[23][24][25] and undoped [26][27][28] Si/SiGe heterostructures. With this in mind, we present in this work a systematic study of the depth dependence of scattering mechanisms in undoped shallow Si/SiGe quantum wells with channel depth ranging from 100 nm to only 10 nm away from the surface, the shallowest Si/SiGe device reported to date.…”

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confidence: 99%

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Scattering mechanisms in shallow undoped Si/SiGe quantum wells

et al. 2015

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We report the magneto-transport study and scattering mechanism analysis of a series of increasingly shallow Si/SiGe quantum wells with depth ranging from ∼ 100 nm to ∼ 10 nm away from the heterostructure surface. The peak mobility increases with depth, suggesting that charge centers near the oxide/semiconductor interface are the dominant scattering source. The power-law exponent of the electron mobility versus density curve, μ ∝ nα, is extracted as a function of the depth of the Si quantum well. At intermediate densities, the power-law dependence is characterized by α ∼ 2.3. At the highest achievable densities in the quantum wells buried at intermediate depth, an exponent α ∼ 5 is observed. We propose and show by simulations that this increase in the mobility dependence on the density can be explained by a non-equilibrium model where trapped electrons smooth out the potential landscape seen by the two-dimensional electron gas.

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Section: Deg Depthsupporting

confidence: 77%

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confidence: 99%

Scattering mechanisms in shallow undoped Si/SiGe quantum wells

et al. 2015

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“…The proposed model utilizes a similarity of QPMR and MagnetoInterSubband (MISO) resistance oscillations. 5,6,[13][14][15] The model considers two spin subbands shifted with respect to each other by Zeeman effect. In each spin subband the energy spectrum evolves in accordance with Landau quantization.…”

Section: Model Of Quantum Electron Transportmentioning

confidence: 99%

“…[5][6][7][8][9][10] These magneto-inter-subband oscillations (MISO) of the resistance are due to an alignment between Landau levels from different subbands i and j with corresponding energies E i and E j . Resistance maxima occur at magnetic fields at which the gap between the bottoms of subbands, ∆ ij = E i − E j , equals a multiple of the Landau level spacing,hω c : ∆ ij = k ·hω c , where k is an integer [11][12][13][14] .…”

Section: Introductionmentioning

confidence: 99%

Quantum electron transport in magnetically entangled subbands

2017

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Transport properties of highly mobile 2D electrons in symmetric GaAs quantum wells with two populated subbands placed in titled magnetic fields are studied at high temperatures. Quantum positive magnetoresistance (QPMR) and magneto-intersubbands resistance oscillations (MISO) are observed in quantizing magnetic fields, B ⊥ , applied perpendicular to the 2D layer. QPMR displays contributions from electrons with considerably different quantum lifetimes, τ (1,2) q , confirming the presence of two subbands in the studied system. MISO evolution with B ⊥ agrees with the obtained quantum scattering times only if an additional reduction of the MISO magnitude is applied at small magnetic fields. This indicates the presence of a yet unknown mechanism leading to MISO damping. Application of in-plane magnetic field produces a strong decrease of both QPMR and MISO magnitude. The reduction of QPMR is explained by spin splitting of Landau levels indicating g-factor, g ≈0.4, which is considerably less than the g-factor found in GaAs quantum well with a single subband populated. In contrast to QPMR the decrease of MISO magnitude is largely related to the in-plane magnetic field induced entanglement between quantum levels in different subbands that, in addition, increases the MISO period.

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“…It was shown [5,6] that one-subband model of resistivity oscillations can be easily extended to the case of two occupied subbands. Then the resistivity tensor is composed of four components with different frequencies and different temperature dependences.…”

Section: Introductionmentioning

confidence: 99%

Influence of Intersubband Scattering on the Magnetic Field Dependence of the Conductivity Tensor

et al. 2006

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In this paper we show that intersubband scattering can lead to apparent inconsistency of the experimental results obtained by means of classical and quantum transport measurements and this discrepancy is entirely connected with the usage of classical formulae to describe magnetic field dependence of a conductivity tensor. We prove that there is no contradiction in our observations and that the models describing quantum oscillations and magnetic-field dependence of the conductivity tensor, which are present in the literature, complement each other.

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Inter-subband scattering in a 2D electron gas

Cited by 131 publications

References 8 publications

Scattering mechanisms in shallow undoped Si/SiGe quantum wells

Scattering mechanisms in shallow undoped Si/SiGe quantum wells

Quantum electron transport in magnetically entangled subbands

Influence of Intersubband Scattering on the Magnetic Field Dependence of the Conductivity Tensor

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