5 research outputs found
Phonon-drag effects on thermoelectric power
We carry out a calculation of the phonon-drag contribution to the
thermoelectric power of bulk semiconductors and quantum well structures for the
first time using the balance equation transport theory extended to the weakly
nonuniform systems. Introducing wavevector and phonon-mode dependent relaxation
times due to phonon-phonon interactions, the formula obtained can be used not
only at low temperatures where the phonon mean free path is determined by
boundary scattering, but also at high temperatures. In the linear transport
limit, is equivalent to the result obtained from the Boltzmann equation
with a relaxation time approximation. The theory is applied to experiments and
agreement is found between the theoretical predictions and experimental
results. The role of hot-electron effects in is discussed. The importance
of the contribution of to thermoelectric power in the hot-electron
transport condition is emphasized.Comment: 8 pages, REVTEX 3.0, 7 figures avilable upon reques
Particle penetration in Kane type semiconductor quantum dots
73.21.Hb Quantum wires,
Ballistic conductance in kane type semiconductor quantum wire
The energy spectrum, ballistic conductance of an electron
on the surface of a Kane type semiconductor hollow cylinder has been
calculated by using the Kane equation with an additional term that takes
into account the spin-orbit (SO) interaction. This term, known as Rashba
term, occurs for asymmetric quantum wells, where two directions on the
normal n are physically nonequivalent. If Rashba spin-orbital interaction is
incorporated into energy spectrum, it leads to the emergence of new extrema.
We obtained electron energy spectrum, which depends on the sign of the
effective spin orbital constant. The energy spectrum of electrons has two
branches when the magnetic field does not exist. One of these branches has
only one minimum while the other branch has one maximum around k =
0 and two minima. The external magnetic field can control these extrema
which occur in the event transport. The results were used to obtain the
ballistic conductance at finite temperature of the Kane type hollow
cylinder. It has been found that the presence of additional local extremum
points in the subband of the electronic spectrum leads to a nonmonotonic
dependence of the ballistic conductance of the system on the chemical
potential. The g-factor of electrons was observed to depend on Rashba
parameter in a linear manner. The effect of finite temperature smears out
the sharp steps in the zero-temperature conductance