We observed Shubnikov-de Haas oscillation and the quantum Hall effect in a high-mobility two-dimensional electron gas polar ZnO/Mg(x)Zn(1-x)O heterostructures grown by laser molecular beam epitaxy. The density could be controlled range of 0.7 x 10(12) to 3.7 per square centimeter tuning magnesium content barriers growth polarity. From temperature dependence amplitude, effective mass electrons was derived as 0.32 +/- 0.03 times free mass. Demonstration an oxide heterostructure presents...

In this paper, recent developments in magnetic tunnel junctions (MTJs) are reported with their potential impacts on integrated circuits. MTJs consist of two metal ferromagnets separated by a thin insulator and exhibit resistances, low (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> ) or high xmlns:xlink="http://www.w3.org/1999/xlink">ap</sub> depending the relative direction ferromagnet magnetizations, parallel (P) antiparallel (AP),...

We investigated electron spin relaxation time ${\ensuremath{\tau}}_{s}$ in $\mathrm{GaAs}/\mathrm{AlGaAs}$ (110) quantum wells (QWs), which a predominant scattering mechanism [D'yakonov-Perel' (DP) mechanism] for conventional (100) QWs is substantially suppressed; was of nanosecond order at room temperature, more than an magnitude longer that the counterpart. The responsible examined by studying quantized energy, mobility, and temperature dependences ${\ensuremath{\tau}}_{s}$. results...

We have fabricated high performance ZnO thin film transistors (TFTs) using CaHfO x buffer layer between channel and amorphous silicon–nitride gate insulator. The TFT structure, dimensions, materials set are identical to those of the commercial silicon (a-Si) TFTs in active matrix liquid crystal display, except for layers replacing a-Si. field effect mobility can be as 7 cm 2 ·V -1 ·s devices with maximum process temperature 300°C. reduced 150°C without much degrading performance, showing...

Conduction electrons are used to optically polarize, detect and manipulate nuclear spin in a (110) GaAs quantum well. Using optical Larmor magnetometry, we find that can be polarized along or against the applied magnetic field, depending on field polarity tilting of sample with respect pump beam. Periodic excitation quantum-confined electron reveals complete spectrum optically-induced quadrupolar-split resonances, as well evidence for delta m = 2 transitions.

Current–voltage characteristics of AlAs/GaAs/AlAs double barrier resonant tunneling diodes with ferromagnetic p-type (Ga, Mn)As on one side and GaAs the other have been studied. A series peaks observed in both polarities, i.e., injecting holes from Mn)As. When are injected side, spontaneous peak splitting has below transition temperature without magnetic field. The dependence is explained by spin valence band

We have investigated the magnetic and magnetotransport properties of (Ga, Mn)As/(Al, Ga)As/(Ga, Mn)As semiconductor-based trilayer structures. observe a weak ferromagnetic interlayer coupling between two layers as well magnetoresistance effects due to spin-dependent scattering tunneling. Both strength ratio decrease with increase temperature and/or Al composition nonmagnetic (Al, Ga)As layer.

Semiconductor quantum dots are potential sources for generating polarization-entangled photons efficiently. The main prerequisite such generation based on biexciton–exciton cascaded emission is to control the exciton fine-structure splitting. Among various techniques investigated this purpose, an electric field a promising means facilitate integration into optoelectronic devices. Here we demonstrate of from single GaAs by field. In contrast previous studies, which were limited In(Ga)As dots,...

We present the transfer of spatially variant polarization topologically structured light to spatial spin texture in a semiconductor quantum well. The electron texture, which is circular pattern with repeating spin-up and spin-down states whose repetition rate determined by topological charge, directly excited vector vortex beam helicity structure. generated efficiently evolves into helical wave owing spin-orbit effective magnetic fields persistent helix state controlling number mode. By...

We demonstrate electrical electron spin injection via interband tunneling in ferromagnetic/nonmagnetic semiconductor Esaki diodes. An tunnel junction between ferromagnetic p + -(Ga,Mn)As and nonmagnetic n -GaAs under reverse-bias allows spin-polarized of electrons from the valence band (Ga, Mn)As to conduction -GaAs. The polarization tunneled is probed by circular electroluminescence (EL) an n-GaAs/InGaAs/p-GaAs light emitting structure integrated with diode. Clear hysteresis loop ±6.5%...

The Hall-plateau width and the activation energy were measured in bilayer quantum Hall state at filling factor \nu=2, 1 2/3, by changing total electron density ratio two wells. Their behavior are remarkably different from one to another. \nu=1 is found stable over all range of difference, while \nu=2/3$ only around balanced point. \nu=2 state, on other hand, shows a phase transition between these types states as changed.

Transport properties of two-dimensional electron gas (2DEG) are studied in selectively doped GaAs/n-AlGaAs heterojunctions, which nanometer-scale InAs dots embedded the vicinity GaAs channel. When distance Wd between dot layer and channel is reduced from 80 to 15 nm, mobility μ electrons at 77 K decreases drastically 1.1×105 1.1 ×103 cm2/V s, while carrier concentration increases 1.1×1011 5.3×1011 cm−2. Such a reduction found only when average thickness above onset level (∼1.5 monolayer) for...

Abstract Quantum wells in InGaAs/AlGaAs with (110) orientation are attractive as active layers spin-controlled lasers circularly polarized emission, while the spin relaxation time is expected to be larger than for (100)-oriented layers. However, hitherto reported recombination lifetimes (40 ps) and times (440 of structures insufficient. Here it shown that higher growth temperatures V/III beam equivalent pressure ratios previously used crystal by molecular epitaxy lead nanosecond range at RT,...

III–V semiconductor quantum wells (QWs) with (110) orientation are expected to serve as a platform for spintronic devices due their ability exhibit prolonged electron spin-relaxation times the order of nanoseconds even at room temperature. Although various mechanisms have been proposed and time has discussed qualitatively, quantitative clarification contribution each mechanism is crucial. In this study, we demonstrate that calculated function quantized energy, temperature, density in...

Time-resolved optical measurements of electron-spin dynamics in a (110) GaAs quantum well are used to study the consequences strongly anisotropic electron g-tensor, and origin previously discovered all-optical nuclear magnetic resonance. All components g-tensor measured, strong anisotropy even along in-plane directions is found. The amplitudes spin signal allow spatial injected its precession axis. Surprisingly efficient dynamic polarization geometry where spins almost transverse applied...

Using time- and spatially-resolved Kerr microscopy, we directly measure the spatiotemporal evolution of photoexcited local spins a two-dimensional electron gas in modulation-doped GaAs/AlGaAs quantum well with top gate electrode. The spatial pattern after diffusion is controlled by voltage that changes strength spin–orbit interaction (SOI) field. By measuring time dependence spin distribution an external magnetic field, successfully observe persistent helix state tuning voltage, obtain both...

We combined scanning tunneling microscopy and locally resolved magnetic stray field measurements on the ferromagnetic semimetal EuB_{6}, which exhibits a complex order colossal magnetoresistance effect. In zero field, spectroscopy visualizes existence of local inhomogeneities in electronic density states, we interpret as localization charge carriers due to formation polarons. Micro-Hall magnetometry total emanating from end rectangular-shaped platelike sample reveals evidence for clusters...

High-sensitivity magnetometry over a wide temperature range has been achieved using submicron GaAs/GaAlAs Hall gradiometry. The sensitivity and versatility of the technique was demonstrated by successful measurement magnetization switching single Fe nanoparticle with m∼5×105 μB (∼5×10−15 emu) at temperatures as high 75 K.

Titanium sponges were infused with bone morphogenetic protein (BMP-Ti), and the osteoinductivity of resultant composite was measured. New formation occurred three weeks after implantation identified by soft x-ray analysis. Quantitative analysis showed no significant difference between BMP-Ti composites control samples (BMP only). Consequently, pure titanium neither inhibited nor promoted BMP activity. Chondrocytes new in direct contact surfaces titanium. X-ray microanalysis demonstrated...

We have measured the x-ray $K$ absorption spectra of $\mathrm{S}$ and ${L}_{\mathrm{III}}$ Nb Mo in layer transition-metal disulfides (Ti${\mathrm{S}}_{2}$, V${\mathrm{S}}_{2}$, Zr${\mathrm{S}}_{2}$, Nb${\mathrm{S}}_{2}$, Mo${\mathrm{S}}_{2}$, Hf${\mathrm{S}}_{2}$, using a Yohan-type curved-crystal spectrometer. These reflect electronic band structures these materials very well exhibit large peak originating empty "$d$" bands broad "metal $\mathrm{sp}$" bands. In combination with...