Spin alignment of electrons in PbTe/(Pb,Eu)Te nanostructures

Grabecki, G.; Wróbel, J.; Dietl, T.; Papis, E.; Kamińska, E.; Piotrowska, A.; Springholz, G.; Bauer, G.

doi:10.1016/s1386-9477(02)00210-2

Cited by 19 publications

(22 citation statements)

References 13 publications

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“…For this reason, observations of the conductance quantization can be used as a tool for detecting potential fluctuations in the host medium. Accordingly, we have demonstrated [9][10][11][12][13][14][15] that in PbTe nanostructures the amplitude of potential fluctuations is strongly suppressed, even in the presence of a significant concentration of charged impurities in the close vicinity of the device. This is concluded from the pronounced 1D quantization in a modulation doped PbTe wires, indicating a rather small backscattering, despite only a few nm separation of the conducting channel from the heavily doped layer.…”

Section: Introductionmentioning

confidence: 90%

“…For appropriate crystallographic orientations, there is a large magnitude of the Landé factor of electrons, g * ≈ 60. Accordingly, the quantized conductance shows a visible spin-splitting of the plateaus already in magnetic fields about 0.2 T [10]. It is well known that if the Fermi energy is adjusted to the spin-gap of the lowest 1D subband, the quantum point contact becomes a spin-dependent barrier.…”

Section: Introductionmentioning

confidence: 94%

“…3a. When the temperature is lowered enough, we start to observe a sequence of quantization steps equal to i×(2e 2 /h), where i represents integral numbers [9][10][11]. An example of such behavior is shown in Fig.…”

Section: Quantum Ballistic Transportmentioning

confidence: 99%

“…This is a result of the large Zeeman splitting in the narrow-gap PbTe, reaching about 70% of the Landau splitting. This subject is considered in more detail in our works [10,14].…”

Section: Quantum Ballistic Transportmentioning

confidence: 99%

“…Therefore, the 2D subband energies are exclusively determined by the well width. This allows for obtaining QWRs of different aspect ratios and different degeneracy of the transverse modes in the electron waveguides [10,13]. Another important property results from the narrow-gap character of PbTe.…”

Section: Introductionmentioning

confidence: 99%

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Ballistic Transport Phenomena in Nanostructures of Paraelectric Lead Telluride

Grabecki

2007

Acta Phys. Pol. A

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This is a review of our recent developments in the physics of lead telluride nanostructures. PbTe is a IV-VI narrow gap paraelectric semiconductor, characterized by the huge static dielectric constant ε > 1000 at helium temperatures. We nanostructurized this material by means of e-beam lithography and wet chemical etching of modulation doped PbTe/Pb 1−x Eu x Te quantum wells. Magnetoresistance measurements performed on the nanostructures revealed a number of magnetosize effects, confirming a ballistic motion of the carriers. The most important observation is that the conductance of narrow constrictions shows a precise zero-field quantization in 2e 2 /h units, despite a significant amount of charged defects in the vicinity of the conducting channel. This unusual result is a consequence of a strong suppression of the Coulomb potential fluctuations in PbTe, an effect confirmed by numerical simulations. Furthermore, the orbital degeneracy of electron waveguide modes can be controlled by the width of PbTe/Pb1−xEuxTe quantum wells, so that unusual sequences of plateau conductance can be observed. Finally, conductance measurements in a nonlinear regime allowed for an estimation of the energy spacing between the one-dimensional subbands.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 94%

Section: Quantum Ballistic Transportmentioning

confidence: 99%

“…This is a result of the large Zeeman splitting in the narrow-gap PbTe, reaching about 70% of the Landau splitting. This subject is considered in more detail in our works [10,14].…”

Section: Quantum Ballistic Transportmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ballistic Transport Phenomena in Nanostructures of Paraelectric Lead Telluride

Grabecki

2007

Acta Phys. Pol. A

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Magnetic Interactions in IV–VI Diluted Magnetic Semiconductors

Górska

Kilański

Łusakowski

2022

Physica Status Solidi (b)

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Diluted magnetic semiconductors (DMS) are interesting because of the interplay between the electronic and magnetic subsystems. Selected magnetic properties of IV–VI DMS are described, looking at the similarities and differences between magnetic properties of II–VI, IV–VI, and III–V DMS. The influence of the crystalline and electronic structure of the material on its magnetic properties is focused on, especially on the exchange interactions among magnetic ions. Methods of determination of the exchange parameters are described by using different experimental techniques, such as measurements of magnetic susceptibility, magnetization, and specific heat. The development in the material technology from bulk crystals to thin films and nanostructures is followed.

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Stern‐Gerlach effect and spin filtering in the solid state

Wróbel

2006

Phys. Status Solidi (c)

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PACS 71.70. Ej, 72.25.Dc, 73.23.Ad Our recent experimental and theoretical works on Stern-Gerlach devices and spin filters built of GaAs and PbTe materials are reviewed. It is shown that for high mobility electrons at the GaAs/(Al,Ga)As interface, the Stern-Gerlach effect can be observed in appropriately designed ballistic nanostructers with in-plane local magnetic field produced by micromagnets of ferromagnetic metals. The spin separation is possible owning to the cancellation of Lorentz force and g-factor enhancement caused by the electron-electron interaction and 1D confinement. Due to a large spin-orbit coupling in PbTe, which results in |g * | ≈ 66, the spinsplitting can become larger than 1D quantization energy in rather weak magnetic fields. Evidences for generation of spin polarised current carried by many 1D subbands in PbTe nanoconstrictions are described.1 Introduction According to the well established quasi-classical arguments [1] the Stern-Gerlach (S-G) effect can not be observed for beams of electrons because of the unavoidable distortions introduced by the Lorentz force. The more recent quantum approaches to this fundamental problem suggested, however, that the (S-G) experiment is difficult but possible for specially prepared electron wave packets [2][3][4]. At the same time it turned out that the physics of electron beams propagating freely in vacuum can provide a sound starting point in the process of developing solid state spintronic devices because of the long spin coherence times in semiconductors [5]. For example, (S-G) effect has been theoretically considered as a possible readout gate in spin-logic processors [6]. The spin filters are also necessary for the Bell inequalities violations tests suggested for the Cooper pair components injected to semiconductor via the Andreev process [7,8]. Also, the progress in fabrication of hybrid ferromagnet-semiconductor microstructures [9, 10] has made it possible to address various aspects of a single-electron motion in the presence of an inhomogeneous magnetic field [11][12][13][14][15][16][17].Such approach, however, should be complemented by taking into account substantial differences between a quasi-classical motion in vacuum and quantum transport in low-dimensional solids, such as the self-consistent nature of a one-electron confining potential, exchange interaction in Fermi liquid, renormalization of the Landé factor and spin-orbit (S-O) effects. In this paper we summarise the outcome of our recent works in which we aimed to take advantage of such differences when developing spin polarizers of semiconductor nanostructures. Experimentally, we studied the effect of a local in-plane magnetic field on ballistic currents in a quantum wire patterned of GaAs/(Al,Ga)As heterostructure. The results are obtained for a ferromagnet-semiconductor hybrid device which is highly optimized in order to toggle between uniform field and field gradient internal spin barriers. The observed effects are attributed to switching between Zeeman and Stern-Gerlach modes -t...

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Spin alignment of electrons in PbTe/(Pb,Eu)Te nanostructures

Cited by 19 publications

References 13 publications

Ballistic Transport Phenomena in Nanostructures of Paraelectric Lead Telluride

Ballistic Transport Phenomena in Nanostructures of Paraelectric Lead Telluride

Magnetic Interactions in IV–VI Diluted Magnetic Semiconductors

Stern‐Gerlach effect and spin filtering in the solid state

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