Angular Dependent Magnetoresistance Oscillationin GaAs/AlxGa1-xAs Superlattice

Yagi, Ryuta; Iye, Yasuhiro; Hashimoto, Yuichi; Odagiri, Takahide; Noguchi, Hiroshi; Sakaki, H.; Ikoma, Toshiaki

doi:10.1143/jpsj.60.3784

Cited by 25 publications

(10 citation statements)

References 8 publications

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“…This was done first in β-(BEDT-TTF)2IBr2 [3], and then in a variety of organic conductors (see reviews [4,5,6]). AMRO were also observed in many other layered materials, such as intercalated graphite [7], Sr2RuO4 [8], Tl2Ba2CuO6 [9,10], and the GaAs superlattices [11,12,13].…”

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confidence: 83%

Angular magnetoresistance oscillations in bilayers in tilted magnetic fields

Yakovenko

Cooper

2006

Physica E: Low-dimensional Systems and Nanostructures

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Angular magnetoresistance oscillations (AMRO) were originally discovered in organic conductors and then found in many other layered metals. It should be possible to observe AMRO to semiconducting bilayers as well. Here we present an intuitive geometrical interpretation of AMRO as the Aharonov-Bohm interference effect, both in real and momentum spaces, for balanced and imbalanced bilayers. Applications to the experiments with bilayers in tilted magnetic fields in the metallic state are discussed. We speculate that AMRO may be also observed when each layer of the bilayer is in the composite-fermion state.

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confidence: 83%

Angular magnetoresistance oscillations in bilayers in tilted magnetic fields

Yakovenko

Cooper

2006

Physica E: Low-dimensional Systems and Nanostructures

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“…AMRO are distinct from the Shubnikov-de Haas and de Haas-van Alphen oscillations and are now widely used for direct mapping of the Fermi surfaces of layered materials [4,5]. AMRO have been observed not only in many organic conductors, but also in intercalated graphite [6], Sr 2 RuO 4 [7], Tl 2 Ba 2 CuO 6 [8,9], and GaAs/AlGaAs superlattices [10]. Early theories of AMRO [4,11,12] were formulated in terms of semiclassical electron trajectories on a cylindrical 3D Fermi surface.…”

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confidence: 99%

Interlayer Aharonov-Bohm Interference in Tilted Magnetic Fields in Quasi-One-Dimensional Organic Conductors

Cooper

Yakovenko

2006

Phys. Rev. Lett.

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Different types of angular magnetoresistance oscillations in quasi-one-dimensional layered materials, such as organic conductors (TMTSF)2X, are explained in terms of Aharonov-Bohm interference in interlayer electron tunneling. A two-parameter pattern of oscillations for generic orientations of a magnetic field is visualized and compared with the experimental data. Connections with angular magnetoresistance oscillations in other layered materials are discussed. AMRO [4,11,12] were formulated in terms of semiclassical electron trajectories on a cylindrical 3D Fermi surface. Then it was realized that AMRO can exist already for two layers [13,14,15], and they represent an Aharonov-Bohm interference effect in interlayer tunneling [16]. Some experimental evidence for AMRO in semiconducting bilayers has been found [17], but more systematic measurements are necessary.AMRO were also found in quasi-one-dimensional (Q1D) organic conductors with open Fermi surfaces, such as (TMTSF) 2 X [3]. These materials consist of parallel chains along the x axis, which form layers with the interlayer spacing d along the z axis and the interchain spacing b along the y axis, as shown in Fig. 1a. Origi- nally, three different AMRO were discovered in the Q1D conductors: the Lebed magic angles [18,19,20,21] for a magnetic field rotation in the (y, z) plane, the Danner, Kang, and Chaikin (DKC) oscillations in the (x, z) plane [22,23], and the third angular effect in the (x, y) plane [24,25,26]. Then Lee and Naughton [27] found combinations of all three effects for generic magnetic field rotations. It became clear that all types of AMRO in Q1D conductors have a common origin and should be explained by a single unified theory.In (TMTSF) 2 X, the in-plane tunneling amplitude between the chains, t b ∼ 250 K [22,23], is much greater than the inter-plane tunneling amplitude t c ∼ 10 K [3]. Thus, we can treat interlayer tunneling as a perturbation and study the interlayer conductivity σ c between just two layers for a tilted magnetic field B = (B x , B y , B z ), as shown in Fig. 1a. This bilayer approach [14,15] only assumes phase memory of interlayer tunneling within a decoherence time τ and does not require a well-defined momentum k z and a coherent 3D Fermi surface. It gives a simple and transparent interpretation of the most general Lee-Naughton oscillations [27] in terms of AharonovBohm interference in interlayer tunneling. The results are equivalent to other approaches based on the classical Boltzmann equation [25,26,27,28,29] and the quantum Kubo formula [30,31,32]. We calculate a contour plots of σ c as a function of two ratios B x /B z and B y /B z for models with one or several interlayer tunneling amplitudes [30,33]. This type of visualization clearly reveals agreement and disagreement between theory and experiment and allows to determine the electronic parameters of the Q1D materials. The results can be also applied to Q1D semiconducting bilayers consisting of quantum wires induced by an array parallel gates, as shown in Fig. 1a.Let us...

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“…Quantum oscillation effects have turned out to be inherent in all degenerate conductors and are observed when the distance between the quantized levels of the electron energy ε = exceeds the temperature-related smearing of the Fermi distribution function of the charge carriers k B T but is considerably less than the Fermi energy ε F , k B T ε F (k B is Boltzmann's constant and T is the temperature). Theoretical and experimental investigations of the electrical conductivity and magnetoresistance in Q2D conductors have been the subject of an enormous number of studies [4][5][6][7][8][9][10][11][12]. In ref.…”

Section: Introductionmentioning

confidence: 99%

Oscillatory thermoelectric effect in quasi-two-dimensional organic conductors in a magnetic field

Krstovska¹,

Galbova²

2007

Can. J. Phys.

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A theoretical analysis is presented of the dependence of the thermoelectric power, when the temperature gradient is directed along the normal to the layers, in a layered conductor, with a quasi-two-dimensional electron energy spectrum on the magnitude and orientation of a strong magnetic field relative to the layers. The angular oscillations of the thermoelectric power, when the magnetic field is noticeably tilted from the normal to the layers result from the periodic dependence of the average electron velocity on the angle between the normal to the layers and the magnetic field. It is shown that, in a quantizing magnetic field at low temperatures, giant quantum oscillations of thermoelectric power as a function of both the magnetic field magnitude and the angle between the normal to the layers and the magnetic field occur. This quantum oscillation effect can be used with a high degree of accuracy as a good spectroscopic method for the experimental study of certain characteristics of a Fermi surface of quasi-two-dimensional organic conductors, such as the quasi-two-dimensionality parameter of the electron energy spectrum, cyclotron effective electron mass, and velocity distribution of charge carriers as well as an accurate determination of the extremal cross sections. PACS No.: 72.15.JfRésumé : Nous présentons une étude théorique de la dépendance de la puissance thermoélectrique en présence d'un gradient de température normal aux couches d'un conducteur qui montrent un spectre électronique quasi 2-D en énergie, en fonction de la grandeur et de l'orientation par rapport à la normale aux couches d'un champ magnétique fort. Les oscillations angulaires de la puissance thermoélectrique, lorsque le champ magnétique est significativement incliné par rapport à la normale aux couches, résulte de la dépendance périodique de la vitesse électronique moyenne sur l'angle entre la normale aux couches et le champ magnétique. Nous montrons que dans un champ magnétique quantifiant à basse température, apparaissent des oscillations quantiques géantes de la puissance thermoélectrique comme fonction à la fois de la grandeur du champ magnétique et de l'angle qu'il fait avec la normale. Cette oscillation quantique peut être utilisée avec haute précision comme méthode spectroscopique pour des études expérimentales de certaines caractéristiques de la surface de Fermi de conducteurs organiques quasi 2-D, comme le paramètre de quasi 2-D du spectre en énergie des électrons, la masse cyclotronique efficace, la distribution en vitesse des porteurs de charge, ainsi que la détermination des sections extrêmales.[Traduit par la Rédaction]

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Angular Dependent Magnetoresistance Oscillationin GaAs/Al_xGa_1-xAs Superlattice

Cited by 25 publications

References 8 publications

Angular magnetoresistance oscillations in bilayers in tilted magnetic fields

Angular magnetoresistance oscillations in bilayers in tilted magnetic fields

Interlayer Aharonov-Bohm Interference in Tilted Magnetic Fields in Quasi-One-Dimensional Organic Conductors

Oscillatory thermoelectric effect in quasi-two-dimensional organic conductors in a magnetic field

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