Interaction effects on magneto-oscillations in a two-dimensional electron gas

Adamov, Yury; Gornyi, I. V.; Mirlin, A. D.

doi:10.1103/physrevb.73.045426

Cited by 55 publications

(64 citation statements)

References 57 publications

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“…We then analyzed our data including the T -dependence of R 0 and assuming that the relative T -dependence of τ q is equal to half the relative T -dependence of R 0 . 26,42 We found that these two different methods yield very similar values for m * within our error bar range (∼ 10%), thus here we only report m * values deduced by assuming that both R 0 and τ q are T -independent. …”

Section: Sample Parameters and Experimental Detailsmentioning

confidence: 62%

Effective mass and spin susceptibility of dilute two-dimensional holes in GaAs

et al. 2011

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We report effective hole mass (m * ) measurements through analyzing the temperature dependence of Shubnikov-de Haas oscillations in dilute (density p ∼ 7 × 10 10 cm −2 , rs ∼ 6) two-dimensional (2D) hole systems confined to a 20 nm-wide, (311)A GaAs quantum well. The holes in this system occupy two nearly-degenerate spin subbands whose m * we measure to be ∼ 0.2 (in units of the free electron mass). Despite the relatively large rs in our 2D system, the measured m * is in reasonably good agreement with the results of our energy band calculations which do not take interactions into account. We then apply a sufficiently strong parallel magnetic field to fully depopulate one of the spin subbands, and measure m * for the populated subband. We find that this latter m * is close to the m * we measure in the absence of the parallel field. We also deduce the spin susceptibility of the 2D hole system from the depopulation field, and conclude that the susceptibility is enhanced by about 50% relative to the value expected from the band calculations.

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Section: Sample Parameters and Experimental Detailsmentioning

confidence: 62%

Effective mass and spin susceptibility of dilute two-dimensional holes in GaAs

et al. 2011

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“…For classically weak perpendicular magnetic field, modification of the Lifshitz-Kosevich-type expression for a 2D electron interacting disordered system has been studied in Refs. [24,25].…”

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confidence: 99%

Temperature derivative of the chemical potential and its magneto-oscillations in a two-dimensional system

et al. 2015

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We report first thermodynamic measurements of the temperature derivative of chemical potential (∂µ/∂T ) in two-dimensional (2D) electron systems. In order to test the technique we have chosen Schottky gated GaAs/AlGaAs heterojunctions and detected experimentally in this 2D system quantum magnetooscillations of ∂µ/∂T . We also present a Lifshits-Kosevitch type theory for the ∂µ/∂T magnetooscillations in 2D systems and compare the theory with experimental data. The magnetic field dependence of the ∂µ/∂T value appears to be sensitive to the density of states shape of Landau levels. The data in low magnetic field domain demonstrate brilliant agreement with theory for non-interacting Fermi gas with Lorentzian Landau level shape.Quantum oscillations are known to be a universal tool to study the electron energy spectrum (Fermi surface cross-sections, electron effective mass and g-factor) in three-dimensional single crystals and two-dimensional (2D) systems. In contrast to the 3D-case, the 2D systems allow in-situ tuning the spectrum and the Fermi energy by various methods (including electric field effect in gated structures, illumination, uniaxial stress etc.), and, hence, allow comprehensive magnetooscillation studies. Quantum oscillations in 2D systems are most often studied in resistivity (Shubnikov-de Haas effect) [ functions µ 1,2 ), the charge of the plates is C(µ 1 − µ 2 )/e, where C is the electric capacitance. Correspondingly, when the two plates are connected electrically and an external parameter varies affecting one of the chemical potential values, a recharging current starts flowing between the plates. The recharging current is proportional to ∆µ (in case the capacitance C varies), ∝ ∂µ/∂n (in case one of the plates is a 2D gas of a density n varying with a gate voltage [6,7]), In our study we apply the technique of measuring ∂µ/∂T similar to that used by Nizhankovskii for bulk samples [10], to the 2D electron systems in magnetic field. We focus on ∂µ/∂T oscillations to compare them with semiclassical theory, and to determine the shape of the density of states of Landau levels. The advantage of the temperature modulation technique is the absence of eddy currents or a background signal (concomitant of many other techniques), and its pure thermodynamic origin.Qualitative discussion. -It is worthwhile to give a qualitative explanation why ∂µ/∂T oscillates with perpendicular magnetic field. For the bare quadratic energy spectrum, ε(p) = p 2 /2m, the single electron density of states is constant in two dimensions. At temperatures T ≪ E F the number of particle-like excitations above µ equals to the number of hole-like excitations below µ (hatched areas in Fig. 1a). Therefore, for a fixed electron density n the chemical potential is independent of temperature, ∂µ/∂T = 0, with exponential accuracy at low temperatures, T ≪ E F , where E F stands for the Fermi energy. In the case of energy dependent density of states (like e.g. in 3D systems, graphene or 2D systems in quantizing magnetic field), one can expand it...

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“…[64]. In addition to experimental motivation related to the apparent metal-insulator transition in two-dimensional systems, the corresponding theory complements the recently developed theory of interaction effects in transport of 2D electrons in zero and non-quantizing magnetic fields [55,56].…”

Section: Interaction Effects On Oscillationsmentioning

confidence: 87%

Magnetotransport of electrons in quantum Hall systems

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Gornyi

et al. 2008

Physica Status Solidi (b)

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Recent theoretical results on magnetotransport of electrons in a 2D system in the range of moderately strong transverse magnetic fields are reviewed. The phenomena discussed include: quasiclassical memory effects in systems with various types of disorder, transport in lateral superlattices, interaction-induced quantum magnetoresistance, quantum magnetooscillations in dc and ac transport, and oscillatory microwave photoconductivity.

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Interaction effects on magneto-oscillations in a two-dimensional electron gas

Cited by 55 publications

References 57 publications

Effective mass and spin susceptibility of dilute two-dimensional holes in GaAs

Effective mass and spin susceptibility of dilute two-dimensional holes in GaAs

Temperature derivative of the chemical potential and its magneto-oscillations in a two-dimensional system

Magnetotransport of electrons in quantum Hall systems

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