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Your search keyword '"SPIN polarization"' showing total 5 results
5 results on '"SPIN polarization"'

1. CONTROLLABLE SPIN POLARIZATION IN A DMS QUANTUM DOT.

Author

KIM, NAMMEE, KANG, T. W., and KIM, HEESANG

Subjects
*DILUTED magnetic semiconductors, *QUANTUM dots, *QUANTUM electronics, *SEMICONDUCTORS, *MAGNETIC semiconductors, *ELECTRON transport, *PHYSICS
Abstract

The effects of electro-magnetic confining potentials and the s–d exchange interaction between substituted Mn ions and carriers on the spin polarization of carriers in an diluted magnetic semiconductor quantum dot are investigated within the framework of the effective-mass theory. The energy eigenvalues and wavefunctions of a single electron in the presence of an external magnetic field are studied by solving the one particle Schrödinger equation including the conventional Zeeman effect, the s–d exchange interaction and the electric confining potential which describes the dot. The eigenenergy structure for low lying states is strongly dependant on the relative sizes of the s–d exchange interactions and the conventional Zeeman energy splitting. When the spin splitting exceeds the cyclotron energy splitting, the Landau level overlappings occur so that the spin polarization of carriers is induced in low lying energy states. This spin polarization of carriers in the diluted magnetic semiconductor quantum dot can be controlled by changing the electro-magnetic confining potentials. [ABSTRACT FROM AUTHOR]

Published
2005
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2. MAGNETIZATION AND MAGNETIC PHASES OF CONDUCTION-BAND DILUTE-MAGNETIC-SEMICONDUCTOR QUANTUM WELLS WITH NON-STEP-LIKE DENSITY OF STATES.

Author

Simserides, Constantinos

Subjects
*MAGNETIC semiconductors, *SPINTRONICS, *MAGNETIC fields, *MAGNETIZATION, *QUANTUM wells, *CONDUCTION bands, *ELECTRIC conductivity, *PHYSICS
Abstract

We study the magnetization and the magnetic phases of II-VI-based n-doped nonmagnetic- semiconductor (NMS) / narrow to wide dilute-magnetic-semiconductor (DMS) / n-doped NMS quantum wells under in-plane magnetic field. The parallel magnetic field is used as a tool, in order to achieve non-step-like density of states in these -appropriate for conduction-band spintronics- structures. [ABSTRACT FROM AUTHOR]

Published
2004
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3. Electron and hole spin cooling efficiency in InAs quantum dots: The role of nuclear field

Author

B. Eble, Valerie Thierry-Mieg, F. Fras, Thierry Amand, Xavier Marie, Christophe Testelin, B. Urbaszek, Jean-Michel Gérard, Aristide Lemaître, Frédéric Bernardot, Maria Chamarro, Audrey Miard, Pascal Desfonds, Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), and Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
III-V semiconductors, Physics and Astronomy (miscellaneous), Dynamic properties, spin dynamics, 7. Clean energy, 01 natural sciences, semiconductor quantum dots, 010305 fluids & plasmas, Spin magnetic moment, Magnetic semiconductors, Condensed Matter::Materials Science, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], 0103 physical sciences, 010306 general physics, Hyperfine structure, Physics, Condensed matter physics, Spin polarization, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Spin quantum number, hyperfine interaction, indium compounds, Quantum dot, Spin Hall effect, Spinplasmonics, Nitrogen-vacancy center, Spin waves
Abstract

International audience; The spin dynamics of a resident carrier, hole or electron, in singly charged InAs/GaAs quantum dots has been measured by pump-probe experiments. The relative strength of the hole to the electron hyperfine couplings with nuclei is obtained by studying the magnetic-field dependence of the resident-carrier spin polarization. We find, in good agreement with recent theoretical studies, that the hole hyperfine coupling is ten times smaller than the electron one.

Published
2010

4. Bidirectional resonant tunneling spin pump

Author

Ting, David Z. -Y., Cartoixà Soler, Xavier, and American Physical Society

Subjects
Physics, Spin pumping, Resonant tunneling, Physics and Astronomy (miscellaneous), Condensed matter physics, Spin polarization, Spin engineering, Spin polarized scanning tunneling microscopy, Quantum effects, Semiconductor device design, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Magnetic semiconductors, Quantum wells, Semiconductors, Electric currents, Magnetic fields, Spin transistor, Spinplasmonics, Spin Hall effect, Heterojunctions, Condensed Matter::Strongly Correlated Electrons, Rashba effect, Spin polarized transport
Abstract

We propose a mechanism for achieving bidirectional spin pumping in conventional nonmagnetic semiconductor resonant tunneling heterostructures under zero magnetic field. The device is designed specifically to take advantage of the special spin configuration described by the Rashba effect in asymmetric quantum wells. It induces the simultaneous flow of oppositely spin-polarized current components in opposite directions through spin-dependent resonant tunneling, and can thus generate significant levels of spin current with very little net electrical current across the tunnel structure, a condition characterized by a greater-than-unity current spin polarization. We also present modeling results on temperature dependence and finite device size effects.

Published
2003

5. Ferromagnetic resonant tunneling diodes as spin polarimeters

Author

Giazotto, F, Taddei, Fazio, R, Beltram, Fazio, Rosario, Beltram, Fabio, Giazotto, Francesco, and Taddei, Fabio

Subjects
heterojunctions, POLARIZATION, Physics and Astronomy (miscellaneous), law.invention, law, ferromagnetic materials, HETEROSTRUCTURES, MAGNETORESISTANCE, POINT-CONTACT, Quantum tunnelling, Diode, Physics, polarization, Spin polarization, Condensed matter physics, diodes, Heterojunction, Magnetic semiconductor, LOCALIZED STATES, JUNCTIONS, Polarizer, Polarization (waves), spin polarization, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, BARRIER, resonant tunneling, Ferromagnetism, SPINTRONICS, Condensed Matter::Strongly Correlated Electrons, ANDREEV REFLECTION, INJECTION, magnetic semiconductors
Abstract

A method for measuring the degree of spin polarization of magnetic materials based on spin-dependent resonant tunneling is proposed. The device we consider is a ballistic double-barrier resonant structure consisting of a ferromagnetic layer embedded between two insulating barriers. A simple procedure, based on a detailed analysis of the differential conductance, allows one to accurately determine the polarization of the ferromagnet. The spin-filtering character of such a system is furthermore addressed. We show that a 100% spin selectivity can be achieved under appropriate conditions. This approach is believed to be well suited for the investigation of diluted magnetic semiconductor heterostructures. (C) 2003 American Institute of Physics.

Published
2003

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