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Semiconductor spintronic devices are considered from the point of view of suitability for digital logic. Functionality of earlier proposed devices is reviewed for cascadability and signal gain. Spin gain transistor, which uses electronic control of ferromagnetism in semiconductors, is treated in more detail via semiconductor Bloch equations for both localized and free-carrier magnetic moments. Dependence of the steady state magnetization and temporal switching characteristics on material parameters is determined. Finally, fundamental physical limits for spintronic devices are determined via use of an idealized model. They are compared with similar limits for electronic devices. It is found that, though spintronic devices switch slower, their switching energy is smaller, therefore they scale with size on a curve with lower power dissipation. [ABSTRACT FROM AUTHOR]

We investigate the effect of a step-doping profile on the spin injection from a ferromagnetic metal contact into a semiconductor quantum well in spin field-effect transistors using a Monte Carlo model. The considered scheme uses a heavily doped layer at the metal-semiconductor interface to vary the Schottky barrier shape and enhance the tunneling current. It is found that spin flux (spin current density) is enhanced proportionally to the total current, and the variation of current spin polarization does not exceed 20%. [ABSTRACT FROM PUBLISHER]

Abstract: In this study, we adopted a current line to produce a localized amperian field and demonstrate the resistance modulation of an InAs two-dimensional electron gas channel with the amperian field. The wafer structure is InAlAs(6nm)/InGaAs(2.5nm)/InAsSQW(2nm)/InGaAs(13.5nm)/InAlAs(20nm). A 90-nm-thick and 3.2-μm-wide gold line, perpendicular to the mesa pattern, was adopted as a source of amperian field. Resistance changes of the mesa wherein the amperian gold line is positioned were measured with a sensing current of 20μA. We obtained 10% of resistance change (R(I Au=10mA)−R(I Au=0))/R(I Au=0) with the current density, J Au=3.47×106 A/cm2, which is comparable with that of the MRAM digit line. The resistance change increases with the amperian current. This result seems to be related to weak localization in the InAs 2DEG system and shows the feasibility of an amperian device to control the resistance of the InAs 2DEG system. [Copyright &y& Elsevier]

Over the last decade, the construction and analysis of spintronic devices have been explored. This mini-review focuses on the basic spintronic phenomena such as giant magnetoresistance, tunnel magnetoresistance, spin transfer torque, spin Hall effect, spin Seebeck effect and BGKC (Bruno – Gnanasekar – Karunakaran – Chandramohan) observation. The mechanism of spin-orbit interaction is theoretically discussed. The in-plane wave vector, magnetic field, bias voltage and the delta potential are influenced on spin-polarized transport in heterostructures. The comparison between the role of Dresselhaus and Rashba spin-orbit interaction in the heterostructure is investigated. The principle of spintronic devices (sensors, magnetic random access memory, unipolar spin diode, spin photodiode, spin LED, spin solar cell, spin FET) and spintronic instruments (spin SEM, spin STM) are also explained. • This mini-review focuses on the basic spintronic phenomena. • The mechanism of Dresselhaus and Rashba spin-orbit interactions are discussed. • The effects of the in-plane wave vector, external field on spin-polarized transport are discussed. • The principles of spintronic devices and instruments are explained. [ABSTRACT FROM AUTHOR]