10 research outputs found
Spin interference and Fano effect in electron transport through a mesoscopic ring side-coupled with a quantum dot
We investigate the electron transport through a mesoscopic ring side-coupled
with a quantum dot(QD) in the presence of Rashba spin-orbit(SO) interaction. It
is shown that both the Fano resonance and the spin interference effects play
important roles in the electron transport properties. As the QD level is around
the Fermi energy, the total conductance shows typical Fano resonance line
shape. By applying an electrical gate voltage to the QD, the total transmission
through the system can be strongly modulated. By threading the mesoscopic ring
with a magnetic flux, the time-reversal symmetry of the system is broken, and a
spin polarized current can be obtained even though the incident current is
unpolarized.Comment: 5 pages, 5 figure
Long-lived charged multiple-exciton complexes in strong magnetic fields
We consider the charged exciton complexes of an ideal two-dimensional
electron-hole system in the limit of strong magnetic fields. A series of
charged multiple-exciton states is identified and variational and finite-size
exact diagonalization calculations are used to estimate their binding energies.
We find that, because of a hidden symmetry, bound states of excitons and an
additional electron cannot be created by direct optical absorption and, once
created, have an infinite optical recombination lifetime. We also estimate the
optical recombination rates when electron and hole layers are displaced and the
hidden symmetry is violated.Comment: 12 pages + 2 PostScript figures, Revtex, Submitted to Phys. Rev. Let
Anomalous molecular dynamics in the vicinity of conical intersections
Conical intersections between molecular electronic potential surfaces greatly
affect various properties of the molecule. Molecular gauge theory is capable of
explaining many of these often unexpected phenomena deriving from the physics
of the conical intersection. Here we give an example of anomalous dynamics in
the paradigm of the Exe Jahn-Teller model, which does not allow a simple
explenation in terms of standard molecular gauge theory. By introducing a dual
gauge theory, we unwind this surprising behavior by identifying it with an
intrinsic spin Hall effect. Thus, this work link knowledge of condensed matter
theories with molecular vibrations. Furthermore, via ab initio calculations the
findings are as well demonstrated to appear in realistic systems such as the
Li3 molecule.Comment: 5 pages, 2 figure
Spontaneous Interlayer Coherence in Double-Layer Quantum Hall Systems: Symmetry Breaking Interactions, In-Plane Fields and Phase Solitons
At strong magnetic fields double-layer two-dimensional-electron-gas systems
can form an unusual broken symmetry state with spontaneous inter-layer phase
coherence. The system can be mapped to an equivalent system of pseudospin
particles with pseudospin-dependent interactions and easy-plane magnetic order.
In this paper we discuss how the presence of a weak interlayer tunneling term
alters the properties of double-layer systems when the broken symmetry is
present. We use the energy functional and equations of motion derived earlier
to evaluate the zero-temperature response functions of the double-layer system
and use our results to discuss analogies between this system and
Josephson-coupled superconducting films. We also present a qualitative picture
of the low-energy charged excitations of this system. We show that parallel
fields induce a highly collective phase transition to an incommensurate state
with broken translational symmetry.Comment: 26 pages, RevTex, 8 postscript figures (submitted to Phys. Rev. B