Contemporary topics in semiconductor spintronics /S Bandyopadhyay.

Preface; Chapter 1. Spin Manipulation in (111) Quantum Wells; 1. Introduction; 2. Symmetry dependence of the BIA and SIA terms in zinc-blende Quantum Wells; 2.1. The Bulk Inversion Asymmetry contribution; 2.2. The Structural Inversion Asymmetry contribution; 2.3. Higher order terms; 2.4. Determination of the spin relaxation time: experimental techniques and samples description; 3. Spin dynamics engineering in (111) zinc-blende quantum wells; 3.1. Electrical control of the electron spin; 3.1.1. Spin relaxation and anisotropy; 3.1.2. Spin diffusion length. 3.2. Determination of the Dresselhaus and Rashba coefficients; 3.3. Substrate orientation dependence; 3.4. Temperature dependence; 3.5. Model; 3.5.1. Simple approach; 3.5.2. Density matrix approach; 4. Perspectives and conclusions; References; Chapter 2. Room Temperature Defect-Engineered Spin Functionalities: Concept and Optimization; 1. Introduction; 2. SDR and the spin-filtering effect; 3. Dynamic spin polarization and spin amplification; 4. Effect of charge state transformation; 5. Effect of doping on spin-filtering efficiency; 6. Effect of competing spin-independent recombination centers. 7. Effect of the defect concentration; 8. Hyperfine interaction and dynamic nuclear polarization; 9. Conditions for complete polarization of the defect nuclear spin; 10. Conclusion; Acknowledgements; References; Chapter 3. Onset of Spin Polarization and Anomalous Conductance in One-dimensional Channels; 1. Introduction; 2. 3D variational model of a narrow constriction; 2.1. General single-particle picture of a long 1D channel; 2.2. Extreme quantum limit and spin dependence; 3. Spin-polarized configurations in a quasi-one-dimensional system. 3.1. Unrestricted Hartree-Fock model of a quantum wire with an applied magnetic field; 3.2. Emergence of spin-polarized regimes; 3.3. Spin polarization in the absence of magnetic field; 3.4. Effects of confinement variations; 4. Transport properties of a modulation-doped GaAs QPC29; 4.1. Description of a QPC structure; 4.2. Hartree-Fock model of a long QPC; 4.3. Electron concentration and effective potential in a QPC; 4.4. The 0.3G0 conductance kink; effects of temperature, QPC length and potential barrier shape on the conductance. 5. Charge conservation, spin polarization and the emergence of the 0.7 structure in a QPC; 5.1. Coexistence of spin-polarized channels under charge conservation; 5.2. The 0.7G0 conductance plateau at the onset of polarization; 5.3. Discussion; 6. Acknowledgments; 7. References; Chapter 4. Coherent Spin Transport in Inorganic Semiconductor Quantum Wires; 1. Introduction; 2. The "spin valve" effect and Hanle conductance oscillation; 3. Spin transport in InSb nanowires; 3.1. Spin valve effect; 3.2. Hanle effect; 3.3. Calculation of relative subband occupancy in the InSb spacer layers

The success of spintronics ― the science and technology of storing, processing, sensing and communicating information using the quantum mechanical spin degree of freedom of an electron ― is critically dependent on the ability to inject, detect and manipulate spins in semiconductors either by incorporating ferromagnetic materials into device architectures or by using external magnetic and electric fields. In spintronics, the controlled generation and manipulation of spin polarization in nonmagnetic semiconductors is required for the design of spin-sensitive devices ranging from spin-qubit hosts, quantum memory and gates, quantum teleporters, spin polarizers and filters, spin-field-effect-transistors, and spin-splitters, among others. One of the major challenges of spintronics is to control the creation, manipulation, and detection of spin polarized currents by purely electrical means. Another challenge is to preserve spin coherence in a device for the longest time or over the longest distance in order to produce reliable spintronic processors. These challenges remain daunting, but some progress has been made recently in overcoming some of the steepest obstacles. This book covers some of the recent advances in the field of spintronics using semiconductors.