Magnetooptical Study of Zeeman Effect in Mn modulation-doped InAs/InGaAs/InAlAs Quantum Well Structures
Ya. V. Terent'ev, S. N. Danilov, H. Plank, J. Loher, D. Schuh, D. Bougeard, D. Weiss, M. V. Durnev, S. A. Tarasenko, I. V. Rozhansky, S. V. Ivanov, D. R. Yakovlev, S. D. Ganichev
We report on a magneto-photoluminescence (PL) study of Mn modulation-doped InAs/InGaAs/InAlAs quantum wells. Two PL lines corresponding to the radiative recombination of photoelectrons with free and bound-on-Mn holes have been observed. In the presence of a magnetic field applied in the Faraday geometry both lines split into two circularly polarized components. While temperature and magnetic field dependences of the splitting are well described by the Brillouin function, providing an evidence for exchange interaction with spin polarized manganese ions, the value of the splitting exceeds the expected value of the giant Zeeman splitting by two orders of magnitude for a given Mn density. Possible reasons of this striking observation are discussed.
We present an analysis of gated InGaAs/InAlAs heterostructures, a device platform to realize spinorbitronic functionalities in semiconductors. The phenomenological model deduced from our magnetotransport experiments allows us to correlate the gate response of the studied two-dimensional electron systems to heterostructure design parameters, in particular the indium concentration. We explain the occurrence of metastable electrostatic configurations showing reduced capacitive coupling and provide gate operation strategies to reach classical field effect control in such heterostructures. Our stud…
We observe an unusual behavior of the low-temperature magnetoresistance of the high-mobility two-dimensional electron gas in InGaAs/InAlAs quantum wells in weak perpendicular magnetic fields. The observed magnetoresistance is qualitatively similar to that expected for the weak localization and anti-localization but its quantity exceeds significantly the scale of the quantum corrections. The calculations show that the obtained data can be explained by the classical effects in electron motion along the open orbits in a quasiperiodic potential relief manifested by the presence of ridges on the qu…
We present a study on the influence of strain-relieving InAlAs buffer layers on metamorphic InAs/InGaAs quantum wells grown by molecular beam epitaxy on GaAs. Residual strain in the buffer layer, the InGaAs barrier and the InAs wells were assessed by X-ray diffraction and high-resolution transmission electron microscopy. By carefully choosing the composition profile and thicknesses of the buffer layer, virtually unstrained InGaAs barriers embedding an InAs quantum well with thickness up to 7nm can be grown. This allows reaching low-temperature electron mobilities much higher than previously re…
Coherent electron spin dynamics in 10-nm-wide InGaAs/InAlAs quantum wells is studied from 10 K to room temperature using time-resolved Kerr rotation. The spin lifetime exceeds 1 ns at 10 K and decreases with temperature. By varying the spatial overlap between pump and probe pulses, a diffusive velocity is imprinted on the measured electron spins and a spin precession in the spin-orbit field is measured. A Rashba symmetry of the SOI is determined. By comparing the spatial precession frequency gradient with the spin decay rate, an upper limit for the Rashba coefficients $α$ of 2$\times$10$^{-12}…
Hereby, we present a comprehensive experimental and theoretical study of the electronic structure and optical properties of excitonic complexes in strain-engineered InGaAs/GaAs quantum dots (QDs) grown by metal-organic chemical vapour deposition and emitting at the 1300 nm telecommunication window. Single QD properties have been determined experimentally for a number of nanostructures by means of excitation-power-dependent and polarization-resolved microphotoluminescence and further compared with the results of confined states calculations employing the 8-band kp theory combined with the confi…
The single electron magnetotransport in a vertical bi-layer semiconductor nanowire made of InAlAs/InGaAs and AlGaAs/GaAs heterostructure is theoretically studied. The magnetic field is directed perpendicularily to the main (transport) axis of the quantum wire and both non-zero components of magnetic field, that is the transverse and the vertical ones, allow to change the magnitude of intra-layer and inter-layer subbands mixing, respectively. We analyze in detail the changes introduced to energy dispersion relation E(k) by strong titled magnetic field up to several teslas for a symmetric and an…
Experiments on resonances of conduction electrons in InGaAs/InAlAs double quantum wells at megagauss magnetic fields in the Faraday geometry are reported. We observe new cyclotron resonances assisted by emission of InAs-like and GaAs-like optic phonons and a combined (cyclotron-spin) resonance assisted by emission of InAs-like phonon. The observations are very well described for three laser frequencies with the use of an eight-band (three level) $\textbf{k}\cdot \textbf{p}$ model, taking into account position- and energy-dependent effective masses and spin g-factors. It is indicated that the n…
The InGaAs-InAlAs-InP high electron mobility transistor (InP HEMT) is the preferred active device used in a cryogenic low noise amplifier (LNA) for sensitive detection of microwave signals. We observed that an InP HEMT 0.3-14GHz LNA at 2K, where the in-going transistors were oriented perpendicular to a magnetic field, heavily degraded in gain and average noise temperature already up to 1.5T. Dc measurements for InP HEMTs at 2K revealed a strong reduction in the transistor output current as a function of static magnetic field up to 14T. In contrast, the current reduction was insignificant when …
