Multicomponent dense electron gas as a model of Si MOSFET

Iordanskǐ, S. V.; Кашуба, А.

doi:10.1134/1.1538290

Cited by 7 publications

(11 citation statements)

References 18 publications

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“…Using the large-q form of Π in Eq. (6), one obtains V q (0) = 2πe 2 q 2 / q 3 + q 3 0 for q ≫ k F , where q 0 = (2α) 1/3 k F ≫ k F is the inverse screening radius in this regime [19]. The main contribution to m * comes from the region of large q and ω in Eq.…”

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confidence: 99%

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Spin-Independent Effective Mass in a Valley-Degenerate Electron System

Gangadharaiah

Maslov

2005

Phys. Rev. Lett.

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In a generic spin-polarized Fermi liquid, the masses of spin-up and spin-down electrons are expected to be different and to depend on the degree of polarization. This expectation is not confirmed by the experiments on two-dimensional heterostructures. We consider a model of an N -fold degenerate electron gas. It is shown that in the large-N limit, the mass is enhanced via a polaronic mechanism of emission/absorption of virtual plasmons. As plasmons are classical collective excitations, the resulting mass does not depend on N , and thus on polarization, to the leading order in 1/N . We evaluate the 1/N corrections and show that they are small even for N = 2.PACS numbers: 71.10.Ay, 71.18.+y, 71.10.Ca The observation of an apparent metal-insulator transition in high-mobility Si metal-oxide-semiconductor-fieldeffect-transistors (MOSFET's) [1] challenged the scaling theory of localization [2], which predicts that a twodimensional (2D) system undergoes only a continuous crossover between weak and strong localization regimes. Although there has been a substantial progress in understanding of transport and thermodynamic properties of MOSFET's and other heterostructures [3,4], the origin of the observed phenomena is still a subject of discussion. Although a conventional (dirty) Fermi-liquid (FL) theory [5,6] can account for many observed effects at least qualitatively and, in some cases, quantitatively, there is also a number of non-FL scenarios for the anomalous metallic state [7,8]. On the experimental side, the main argument for the FL-nature of the metallic state is the observation of quite conventional Shubnikov-de Haas (ShdH) oscillations [3,4], which implies an existence of well-defined quasiparticles albeit with the renormalized effective mass m * and spin susceptibility χ * s . The ShdH and magnetoresistance experiments show that at low densities both m * and χ * s are significantly enhanced compared to their band values [4] and, according to some studies [9,10], even diverge at the resistive transition point.Although none drastically non-FL features of the metallic state have been found in ShdH measurements as of now, there is one very intriguing observation which does seem to present a challenge for the FL theory, at least in its conventional formulation. Namely, in all studies when the spin and orbital degrees of freedom were controlled independently by applying a tilted magnetic field, the effective masses, m * ↑ and m * ↓ , and Dingle temperatures (impurity scattering rates), T D↑ and T D↓ , of spin-up and -down electrons, were found to be almost the same. Moreover, m * in MOSFETs [11,12] was found to be independent of the spin polarization, whereas T D was shown to depend on the polarization only weakly. In n-GaAs, the effective mass was found to depend on the parallel magnetic field [13]; however, this behavior was attributed to the coupling between the in-and out-ofplane degrees of freedom (Stern effect [14]), which is to be expected in systems with wider quantum wells. Given that the Stern effect is...

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confidence: 99%

“…To this end, we turn to a model of a Coulomb gas with large degeneracy N , considered previously in Refs. [18], [19]. This model is relevant, first of all, to valley-degenerate systems, such as the (001) surface of a Si MOSFET, where N = 4 (two valleys and two spin projections).…”

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confidence: 99%

Spin-Independent Effective Mass in a Valley-Degenerate Electron System

Gangadharaiah

Maslov

2005

Phys. Rev. Lett.

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“…As it is also the case for the Coulomb interaction, 14,15 the effective mass in the N U m ≫ 1 limit does not depend on N . Note that Eq.…”

Section: 10)mentioning

confidence: 63%

“…Fermiliquid properties of such a system were discussed both in terms of RG 13 and pertubation theory for the case of a Coloumb interaction. 14,15 In the limit when the N times a (dimensionless) coupling constant is larger than one, renormalization of not only the Z factor but also of the effective mass comes from energies much higher than the Fermi energy. Based on the observation, the authors of Ref.…”

Section: Higher Orders Of the Perturbation Theorymentioning

confidence: 99%

Universal and nonuniversal renormalizations in Fermi liquids

Chubukov

Maslov

2010

Phys. Rev. B

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We discuss an interplay between the Fermi-liquid (FL) theory and diagrammatic perturbative approach to interacting Fermi systems. In the FL theory for Galilean-invariant systems, mass renormalization m * /m comes exclusively from fermions at the Fermi surface. We show that in a diagrammatic perturbation theory the same result for m * /m comes from fermions both at and away from the Fermi surface. The equivalence of the FL and pertubative approaches is based on a particular relation between self-energy contributions from high-and low-energy fermions. We argue that care has to be exercised in the renormalization group approach to a FL in order not to miss the high-energy contribution to m * /m. As particular examples, we discuss m * /m and the quasiparticle residue Z for 2D and 3D systems with both SU (2) and SU (N ) symmetries, and with a short-range interaction. We derive an expression for the anisotropic part of the Fermi-liquid vertex in the large-N limit of the SU (N ) case.

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“…We first assume and then verify that in the current regime Ω l ∼ ω and Q 2 /m ∼ ω, i..e, |Q| ∼ √ mω k F . The polarization bubble for |Q| k F can be approximated as 27,40,41…”

Section: High Frequencies: ω Efmentioning

confidence: 99%

Dynamical susceptibility of a Fermi liquid

2018

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We study dynamic response of a Fermi liquid in the spin, charge and nematic channels beyond the random phase approximation for the dynamically screened Coulomb potential. In all the channels, one-loop order corrections to the irreducible susceptibility result in a non-zero spectral weight of the corresponding fluctuations above the particle-hole continuum boundary. It is shown that the imaginary part of the spin susceptibility, Imχs(q, ω), falls off as q 2 /ω for frequencies above the continuum boundary (ω vFq) and below the model-dependent cutoff frequency, whereas the imaginary part of the charge susceptibility, Imχc(q, ω), falls off as (q/kF ) 2 q 2 /ω for frequencies above the plasma frequency. An extra factor of (q/kF ) 2 in Imχc(q, ω) as compared to Imχs(q, ω) is a direct consequence of Galilean invariance. The imaginary part of the nematic susceptibility increases linearly with ω up to a peak at the ultraviolet energy scale-the plasma frequency and/or Fermi energy-and then decreases with ω. We also obtain explicit forms of the spin susceptibility from the kinetic equation in the collisionless limit and for the Landau function that contains up to first three harmonics. arXiv:1806.10159v1 [cond-mat.str-el]

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Multicomponent dense electron gas as a model of Si MOSFET

Cited by 7 publications

References 18 publications

Spin-Independent Effective Mass in a Valley-Degenerate Electron System

Spin-Independent Effective Mass in a Valley-Degenerate Electron System

Universal and nonuniversal renormalizations in Fermi liquids

Dynamical susceptibility of a Fermi liquid

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