Instability of the two-dimensional metallic phase to a parallel magnetic field

Pudalov, V. M.; Brunthaler, G.; Prinz, A.; Bauer, G.

doi:10.1134/1.567445

Cited by 134 publications

(136 citation statements)

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“…For a thin 2D electron system with thickness much smaller than the magnetic length, the inplane magnetic field only affects the degree of the spin polarization. The resistance, R, increases with B until the full spin polarization is reached and saturates after that [1][2][3][4][5][6][7][8], which is explained in terms of the dependence of the screening of the random potential on the degree of spin polarization [9]. Being a spin effect, the parallel field-induced magnetoresistance should not depend on the mutual orientation of the field B and current I [10].…”

Section: Introductionmentioning

confidence: 99%

Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells

Mel'nikov

Dolgopolov

Shashkin

et al. 2017

Journal of Applied Physics

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We find an unusual anisotropy of the inplane field magnetoresistance with higher resistance in the parallel orientation of the field, B , and current, I, in ultra-high mobility SiGe/Si/SiGe quantum wells. The anisotropy depends on the orientation between the inplane field and current relative to the crystallographic axes of the sample and is a consequence of the ridges on the quantum well surface. For the parallel or perpendicular orientations between current and ridges, a method of converting the magnetoresistance measured at I ⊥ B into the one measured at I B is suggested and is shown to yield results that agree with the experiment.

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Section: Introductionmentioning

confidence: 99%

Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells

Mel'nikov

Dolgopolov

Shashkin

et al. 2017

Journal of Applied Physics

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“…For non-interacting electrons in disordered systems [1] the scaling hypothesis of localization [2] can successfully predict many of the universal features of the MIT. However, the influence of many-particle interactions on the MIT is not equally well understood [3] and recent investigations of an apparent MIT in two-dimensional systems even question the main assumptions of the scaling hypothesis [4][5][6]. In the single-particle case, the one-dimensional quasiperiodic Aubry-André model is known rigorously to exhibit an MIT for all states in the spectrum as a function of the quasiperiodic potential strength µ [7].…”

Section: Introductionmentioning

confidence: 99%

Interacting particles at a metal-insulator transition

2002

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We study the influence of many-particle interaction in a system which, in the single particle case, exhibits a metal-insulator transition induced by a finite amount of onsite pontential fluctuations. Thereby, we consider the problem of interacting particles in the one-dimensional quasiperiodic Aubry-André chain. We employ the density-matrix renormalization scheme to investigate the finite particle density situation. In the case of incommensurate densities, the expected transition from the single-particle analysis is reproduced. Generally speaking, interaction does not alter the incommensurate transition. For commensurate densities, we map out the entire phase diagram and find that the transition into a metallic state occurs for attractive interactions and infinite small fluctuations -in contrast to the case of incommensurate densities. Our results for commensurate densities also show agreement with a recent analytic renormalization group approach. 71.30.+h,71.27.+a

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“…In the metallic phase in Si-MOSFET's with high peak electron mobilities of µ peak > ∼ 2 m 2 /V s, the diagonal resistivity ρ xx shows a sharp drop with decreasing temperature from about 2 K [1]. Recent experiments [8,9] show that magnetic fields applied parallel to the 2D plane suppress the low temperature metallic conduction in Si-MOSFET's. Since the parallel magnetic field does not couple the orbital motion of electrons, this fact suggests an important role of the spin of electrons.…”

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confidence: 99%

Spin Degree of Freedom in a Two-Dimensional Electron Liquid

et al. 1999

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We have investigated correlation between spin polarization and magnetotransport in a high mobility silicon inversion layer which shows the metal-insulator transition. Increase in the resistivity in a parallel magnetic field reaches saturation at the critical field for the full polarization evaluated from an analysis of low-field Shubnikov-de Haas oscillations. By rotating the sample at various total strength of the magnetic field, we found that the normal component of the magnetic field at minima in the diagonal resistivity increases linearly with the concentration of "spin-up" electrons. 71.30.+h, 73.40.Qv, 73.40.Hm A metal-insulator transition (MIT) observed in Si metal-oxide-semiconductor field-effect transistors [1,2] (Si-MOSFET's) and other systems [3-6] attracts a great deal of attention since it seems to contradict an important result of the scaling theory by Abrahams et al. [7] that the conductance of a disordered two-dimensional (2D) system at zero magnetic field goes to zero for T → 0. In the metallic phase in Si-MOSFET's with high peak electron mobilities of µ peak > ∼ 2 m 2 /V s, the diagonal resistivity ρ xx shows a sharp drop with decreasing temperature from about 2 K [1]. Recent experiments [8,9] show that magnetic fields applied parallel to the 2D plane suppress the low temperature metallic conduction in Si-MOSFET's. Since the parallel magnetic field does not couple the orbital motion of electrons, this fact suggests an important role of the spin of electrons. However, the mechanism of the conduction in the anomalous metallic phase is not clear yet.The 2D systems that show the MIT [1-6] are characterized by strong Coulomb interaction between electrons. The mean Coulomb energy per electron U = (πN s ) 1/2 e 2 /4πε 0 κ is larger than the mean kinetic energy K = πh 2 N s /m * by an order of the magnitude around the critical point for the MIT. Here, N s is the electron concentration, κ is the relative dielectric constant at the interface, and m * is the effective mass of electron. It is estimated that U = 120 K, K = 14 K and the ratio r s = U/K = 8.3 for κ = 7.7 and m * = 0.19m e at N s = 1 × 10 15 m −2 in Si-MOSFET's. The ground state of the insulating phase of high mobility Si-MOSFET's is considered to be a pinned Wigner solid (WS) [10,11]. Magnetic field dependence of the thermal activation energy observed for various angles of the magnetic field was essentially explained by a model based on magnetic interactions in the pinned WS [12,13]. Although the quantum fluctuations change the 2D system into a liquid at higher-N s , electron-electron (e-e) interaction is expected to be still important.In the conduction band of silicon, the spin-orbit interaction is negligible and the spin polarization p = (N ↑ − N ↓ )/N s can always be given in the direction to the magnetic field. Here N ↑ and N ↓ are the concentrations of electrons having an up spin and a down spin, respectively (N s = N ↑ + N ↓ ). In the present work, we investigate the low temperature conduction in a high mobility Si-MOSFET for vario...

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Instability of the two-dimensional metallic phase to a parallel magnetic field

Cited by 134 publications

References 10 publications

Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells

Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells

Interacting particles at a metal-insulator transition

Spin Degree of Freedom in a Two-Dimensional Electron Liquid

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