Spin Hall effect on edge magnetization and electric conductance of a 2D semiconductor strip

The intrinsic spin Hall effect on spin accumulation and electric conductance in a diffusive regime of a 2D electron gas has been studied for a 2D strip of a finite width. It is shown that the spin polarization near the flanks of the strip, as well as the electric current in the longitudinal direction, exhibit damped oscillations as a function of the width and strength of the Dresselhaus spin-orbit interaction. Cubic terms of this interaction are crucial for spin accumulation near the edges. As expected, no effect on the spin accumulation and electric conductance have been found in case of Rashba spin-orbit interaction.

Strain-induced coupling of spin current to nanomechanical oscillations

We propose a setup which allows us to couple the electron spin degree of freedom to the mechanical motions of a nanomechanical system not involving any of the ferromagnetic components. The proposed method employs the strain-induced spin-orbit interaction of electrons in narrow gap semiconductors. We have shown how this method can be used for detection and manipulation of the spin flow through a suspended rod in a nanomechanical device.

Terahertz conductivity and possible BLOCH gain in semiconductor superlattices

We have investigated terahertz emission due to dynamical electron transport in wide-miniband GaAs/Al(0.3)Ga0.7As superlattices. By noting that the time-domain THz emission spectroscopy inherently measures the step-response of the electron system to the bias electric field, the obtained THz spectra were compared with the high-frequency conductivities predicted for miniband transport. Excellent agreement between theory and experiment strongly supports that the THz gain due to Bloch oscillating electrons persists at least up to 1.7 THz. It was also found that Zener tunneling into the second miniband sets the high-frequency limit to the THz gain for the samples studied here.

Opto-thermionic refrigeration in semiconductor heterostructures

Combining the ideas of laser cooling and thermionic cooling, we have proposed an opto-thermionic cooling process, and investigated its cooling effect caused by the light emission from a quantum well embedded into a semiconductor pn junction. For a GaAs/AlGaAs opto-thermionic refrigerator in which the Auger recombination is the major nonradiative process, cooling can be achieved in a finite range of bias voltage. Using the measured values of the Auger coefficient, our calculated cooling rate is at least several watts/cm(2).