Magnetoresistance of a two-dimensional electron gas in nearly parallel magnetic fields

Středa, P.; Vašek, P.; Cukr, M.

doi:10.1103/physrevb.51.11144

Cited by 14 publications

(12 citation statements)

References 7 publications

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“…In tilted magnetic fields, the strong increase in resistance with the tilt angle, i.e with the growing perpendicular component of the field, Β┴, is observed for a given Βμ . This behaviour is in agreement with the previous measurements on standard GaAS/AlGaAs heterostructures with approximately triangular quantum wells [5,6] and can be understood within the framework of a standard magneto transport theory [7]. According to this theory the magnetoresistance of the system with a closed Fermi line of a noncircular shape and an anisotropic relaxation time is positive and saturates at high B1.…”

Section: (981)supporting

confidence: 90%

In-Plane/Tilted Magnetic-Field-Dependent Conductance of 2D Electron Systems in Asymmetric Double Quantum Wells

et al. 1997

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The resistance in an asymmetric double-well structure was measured as a function of magnetic fields oriented almost parallel to the plane of the electron 1ayer. It was shown that the shape of the magnetoresistance curves is close to the in-plane magnetic-field-dependent density of states which we obtained by self-consistent numerical calculation. The novel feature is the negative magnetoresistance observed at low magnetic fields.

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Section: (981)supporting

confidence: 90%

In-Plane/Tilted Magnetic-Field-Dependent Conductance of 2D Electron Systems in Asymmetric Double Quantum Wells

et al. 1997

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“…This relative magnitude of the two magnetoresistances persists over a range of sample parameters and is opposite to the relative magnitude oberved in one particular sample. 11 We have no explanantion for this difference. It should also be noted that the experimental magnetoresistance tends not to saturate, but passes through a maximum before falling at higher magnetic fields.…”

Section: B Evaluation Of the Scattering Elementsmentioning

confidence: 96%

Transverse magnetoresistance of GaAs/AlxGa1−
Heisz
¹
,
Zaremba
²

1996
Phys. Rev. B
23
1
14
0
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We have calculated the resistivity of a GaAs/AlGaAs heterojunction in the presence of both an in-plane magnetic field and a weak perpendicular component using a semiclassical Boltzmann transport theory. These calculations take into account fully the distortion of the Fermi contour which is induced by the parallel magnetic field. The scattering of electrons is assumed to be due to remote ionized impurities. A positive magnetoresistance is found as a function of the perpendicular component, in good qualitative agreement with experimental observations. The main source of this effect is the strong variation of the electronic scattering rate around the Fermi contour which is associated with the variation in the mean distance of the electronic states from the remote impurities. The magnitude of the positive magnetoresistance is strongly correlated with the residual acceptor impurity density in the GaAs layer. The carrier lifetime anisotropy also leads to an observable anisotropy in the resistivity with respect to the angle between the current and the direction of the in-plane magnetic field.

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“…Positive B-dependence in the high-B region is also seen. Since similar positive magnetoresistance appears in 2DEGs covered with nonmagnetic materials, it should be attributed to intrinsic effects of 2DEGs, such as the orbital effect owing to the finite thickness of the inversion layer [29,30], or the resistivity increase induced by the spin polarization [31,32]. On the other hand, it is hard to explain the negative magnetoresistance observed in the low-B region for Θ = 0.42 ML [ Fig.…”

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confidence: 99%

Evidence for Two-Dimensional Spin-Glass Ordering in Submonolayer Fe Films on Cleaved InAs Surfaces

2008

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Magnetotransport measurements have been performed on two-dimensional electron gases formed at InAs(110) surfaces covered with a submonolayer of Fe. Hysteresis in the magnetoresistance, a difference in remanent magnetoresistance between zero-field-cooling procedures and field-cooling procedures, and logarithmic time-dependent relaxation after magnetic field sweep are clearly observed at 1.7 K for a coverage of 0.42 monolayer. These features are associated with spin-glass ordering in the Fe film.PACS numbers: 75.70. Ak, 73.25.+i, 75.50.Lk Spin glasses are magnetic systems with randomly competing interactions. They have attracted great interest during the last few decades [1,2,3]. Spin-glass models and related methods have also been useful in other areas of science such as simulation of protein folding [4] and optimization problems in computer science [5]. Most of the attempts to understand spin glasses have been concerned with the behavior in three dimensions. It is generally believed that, in two dimensions, the spin-glass ordering does not occur at nonzero temperature. The lower critical dimension of spin-glass ordering has been shown to be d l > 2 for Heisenberg spins [6] and XY spins [7], and Ising spins with Gaussian distribution of disorder [8,9]. Although the situation for the Ising model with bimodal (±J) disorder was controversial [10,11], recent theoretical investigations do not support the existence of the spin-glass phase for T > 0 [12,13,14]. On the other hand, numerical calculations have demonstrated that the spin-glass-like ordering temperature can be nonzero for a two-dimensional (2D) Ising model with random nearestneighbor interactions and ferromagnetic second-neighbor interactions [15,16]. Experimentally, spin-glass behavior was found in thin films [17,18,19,20] and layered compounds [21,22,23]. However, no observation has been reported for a single layer system with strict two dimensionality.Submonolayer films of magnetic materials adsorbed on nonmagnetic substrates are promising candidates for 2D spin-glass systems. A random distribution of adsorbates can be obtained by deposition at low substrate temperatures, where surface diffusion is minimal and island growth is limited. In the case that the sign of the interaction depends on the relative position of adatoms, a competition between ferromagnetic and antiferromagnetic interactions is expected. As the substrate, narrow band-gap III-V semiconductors have a remarkable property. It is well known that a two-dimensional electron gas (2DEG) can be easily formed on the surface of InAs and InSb. Photoelectron spectroscopy measurements have shown that the position of the Fermi level lies above the conduction-band minimum at cleaved (110) surfaces with various kinds of adsorbed materials [24,25]. Recently the present authors have performed magnetotransport measurements on inversion layers formed on cleaved surfaces of p-type InAs [26,27] and InSb [28] covered with submonolayers of Ag or alkali metals. The observed coverage dependence of the Hall mobi...

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Magnetoresistance of a two-dimensional electron gas in nearly parallel magnetic fields

Cited by 14 publications

References 7 publications

In-Plane/Tilted Magnetic-Field-Dependent Conductance of 2D Electron Systems in Asymmetric Double Quantum Wells

In-Plane/Tilted Magnetic-Field-Dependent Conductance of 2D Electron Systems in Asymmetric Double Quantum Wells

Transverse magnetoresistance of GaAs/AlxGa1−
Heisz
¹
,
Zaremba
²

1996
Phys. Rev. B
23
1
14
0
View full text Add to dashboard Cite

Evidence for Two-Dimensional Spin-Glass Ordering in Submonolayer Fe Films on Cleaved InAs Surfaces

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Magnetoresistance of a two-dimensional electron gas in nearly parallel magnetic fields

Cited by 14 publications

References 7 publications

In-Plane/Tilted Magnetic-Field-Dependent Conductance of 2D Electron Systems in Asymmetric Double Quantum Wells

In-Plane/Tilted Magnetic-Field-Dependent Conductance of 2D Electron Systems in Asymmetric Double Quantum Wells

Transverse magnetoresistance of GaAs/AlxGa1−Heisz1, Zaremba2 1996Phys. Rev. B231140View full textAdd to dashboardCite

Evidence for Two-Dimensional Spin-Glass Ordering in Submonolayer Fe Films on Cleaved InAs Surfaces

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Transverse magnetoresistance of GaAs/AlxGa1−
Heisz
¹
,
Zaremba
²

1996
Phys. Rev. B
23
1
14
0
View full text Add to dashboard Cite