476 research outputs found
Scattering of a Dirac electron on a mass barrier
The interaction of a wave packet (and in particular the wave front) with a
mass barrier is investigated in one dimension. We discuss the main features of
the wave packet that are inherent to two-dimensional wave packets, such as
compression during reflection, penetration in the case when the energy is lower
than the height of the barrier, waving tails, precursors, and the retardation
of the reflected and penetrated wave packets. These features depend on the
wave-packet envelope function which we demonstrate by considering the case of a
rectangular wave packet with sharp front and trailing edges and a smooth
Gaussian wave packet. The method of Fourier integral for obtaining the
nonstationary solutions is used.Comment: 12 pages, 9 figure
Wigner crystallization in the two electron quantum dot
Wigner crystallization can be induced in a quantum dot by increasing the
effective electron-electron interaction through a decrease of the electron
density or by the application of a strong magnetic field. We show that the
ground state in both cases is very similar but the energy scales are very
different and therefore also the dynamics.Comment: 4 pages, 4 figure
Power-law dependence of the angular momentum transition fields in few-electron quantum dots
We show that the critical magnetic fields at which a few-electron quantum dot
undergoes transitions between successive values of its angular momentum (M),
for large M values follow a very simple power-law dependence on the effective
inter-electron interaction strength. We obtain this power law analytically from
a quasi-classical treatment and demonstrate its nearly-universal validity by
comparison with the results of exact diagonalization.Comment: Uses RevTeX4, 6 figures included in the tex
Confinement of two-dimensional excitons in a non-homogeneous magnetic field
The effective Hamiltonian describing the motion of an exciton in an external
non-homogeneous magnetic field is derived. The magnetic field plays the role of
an effective potential for the exciton motion, results into an increment of the
exciton mass and modifies the exciton kinetic energy operator. In contrast to
the homogeneous field case, the exciton in a non-homogeneous magnetic field can
also be trapped in the low field region and the field gradient increases the
exciton confinement. The trapping energy and wave function of the exciton in a
GaAs two-dimensional electron gas for specific circular magnetic field
configurations are calculated. The results show than excitons can be trapped by
non-homogeneous magnetic fields, and that the trapping energy is strongly
correlated with the shape and strength of the non-homogeneous magnetic field
profile.Comment: 9 pages, 12 figure
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