Asymmetric Semiconductor Heterostructures Research Articles

Mechanism of the photoelectromagnetic effect in two-dimensional systems in quantizing magnetic fields

A new mechanism of the photovoltaic effect in a terahertz frequency range is proposed that is capable of explaining the features of terahertz photocurrents observed previously in asymmetric InAs quantum wells and double GaAs quantum wells in an external tilted magnetic field. It is shown that, in the asymmetric semiconductor heterostructures occurring in a tilted magnetic field, an edge photocurrent is generated due to the absorption of radiation on the electron transitions between Landau levels. A new approach to the creation of highly sensitive terahertz photodetectors based on asymmetric semiconductor heterostructures is proposed.

Magnetic focusing of charge carriers from spin-split bands: semiclassics of a Zitterbewegung effect

We present a theoretical study of the interplay between cyclotron motion and spin splitting of charge carriers in solids. While many of our results apply more generally, we focus especially on the Rashba model describing electrons in the conduction band of asymmetric semiconductor heterostructures. Appropriate semiclassical limits are distinguished that describe various situations of experimental interest. Our analytical formulae, which take full account of Zeeman splitting, are used to analyse recent magnetic-focusing data. Surprisingly, it turns out that the Rashba effect can dominate the splitting of cyclotron orbits even when the Rashba and Zeeman spin-splitting energies are of the same order. We also find that the origin of spin-dependent cyclotron motion can be traced back to Zitterbewegung (ZB)-like oscillatory dynamics of charge carriers from spin-split bands. The relation between the two phenomena is discussed, and we estimate the effect of ZB-related corrections to the charge carriers' canonical position.

Inverse Faraday effect in conducting crystals caused by a broken mirror symmetry

We consider how the absense of mirror crystal symmetry influences electron kinetics of polar metals, semiconductors, asymmetric semiconductor heterostructures as well as some layered antipyroelectric high- T c compounds. We find that illumination of such crystals by circularly polarized infrared light should induce a permanent spin orientation of current carriers in an amount proportional to i c( c·ε×ε ∗) , where ε is the polarization vector and c is a unit vector directed either along the polar or antipyroelectric axis or perpendicular to the semiconductor heterostructure.

Spin-dependent electronic tunneling at zero magnetic field

The spin-dependent tunneling phenomenon in symmetric and asymmetric semiconductor heterostructures at zero magnetic field is studied theoretically on the base of a single conduction band and spin-dependent boundary conditions approach. It is shown that the spin-orbit splitting in the dispersion relation for the electrons in ${A}_{\mathrm{III}}{B}_{\mathrm{V}}$ semiconductor quantum-tunneling structures can provide a dependence of the tunneling transmission probability on the electron's spin polarization. The dependence is calculated and discussed for different kinds of tunnel heterostructures.