| 1. |
- Antonyuk, Vadim, et al.
(författare)
-
Phonon transmission in III-V semiconductor superlattices and alloys
- 2005
-
Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 20:5, s. 347-352
-
Tidskriftsartikel (refereegranskat)abstract
- We have used the transfer matrix approach to investigate the LA phonon transmission along the [0 0 1] growth direction in GaAs/GaAlAs superlattices and in Ga1-xAlxAs alloys. Our calculated minigap in the phonon dispersion induced by the zone folding matches reasonably to the phonon filtering experiment. However, in the regime of phonon ballistic transport, we found insignificant effect of zone folding on phonon thermal conductance. On the other hand, the alloy scatterings largely suppress the phonon transmission probability and so lower the phonon thermal conductance of alloys.
|
|
| 2. |
- Chao, Koung-An, et al.
(författare)
-
Room-temperature semiconductor heterostructure refrigeration
- 2005
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:2
-
Tidskriftsartikel (refereegranskat)abstract
- With the proper design of semiconductor tunneling barrier structures, we can inject low-energy electrons via resonant tunneling, and take out high-energy electrons via a thermionic process. This is the operation principle of our semiconductor heterostructure refrigerator (SHR) without the need of applying a temperature gradient across the device. Even for the bad thermoelectric material AlGaAs, our calculation shows that at room temperature, the SHR can easily lower the temperature by 5 - 7 K. Such devices can be fabricated with the present semiconductor technology. Besides its use as a kitchen refrigerator, the SHR can efficiently cool microelectronic devices.
|
|
| 3. |
- Mal'shukov, AG, et al.
(författare)
-
Spin Hall conductivity of a disordered two-dimensional electron gas with Dresselhaus spin-orbit interaction
- 2005
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 71:12
-
Tidskriftsartikel (refereegranskat)abstract
- The spin Hall conductivity of a disordered two-dimensional electron gas has been investigated for a general spin-orbit interaction. We have found that in the diffusive regime of electron transport, the dc spin-Hall conductivity of a homogeneous system is zero due to impurity scattering when the spin-orbit coupling contains only the Rashba interaction, in agreement with existing results. However, when the Dresselhaus interaction is taken into account, the spin-Hall current is not zero. We also considered the spin-Hall currents induced by an inhomogeneous electric field. It is shown that a time-dependent electric charge induces a vortex of spin-Hall currents.
|
|
| 4. |
- Mal'shukov, AG, et al.
(författare)
-
Spin Hall effect on edge magnetization and electric conductance of a 2D semiconductor strip
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114. ; 95:14
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 5. |
- Mal'shukov, AG, et al.
(författare)
-
Strain-induced coupling of spin current to nanomechanical oscillations
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114. ; 95:10
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 6. |
- Tang, CS, et al.
(författare)
-
Generation of spin current and polarization under dynamic gate control of spin-orbit interaction in low-dimensional semiconductor systems
- 2005
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 71:19
-
Tidskriftsartikel (refereegranskat)abstract
- Based on the Keldysh formalism, the Boltzmann kinetic equation and the drift-diffusion equation have been derived for studying spin-polarization flow and spin accumulation under effect of the time-dependent Rashba spin-orbit interaction in a semiconductor quantum well. The time-dependent Rashba interaction is provided by time-dependent electric gates of appropriate shapes. Several examples of spin manipulation by gates have been considered. Mechanisms and conditions for obtaining the stationary spin density and the induced rectified dc spin current are studied.
|
|
