283 research outputs found
Dissipationless electron transport in photon-dressed nanostructures
It is shown that the electron coupling to photons in field-dressed
nanostructures can result in the ground electron-photon state with a nonzero
electric current. Since the current is associated with the ground state, it
flows without the Joule heating of the nanostructure and is nondissipative.
Such a dissipationless electron transport can be realized in strongly coupled
electron-photon systems with the broken time-reversal symmetry - particularly,
in quantum rings and chiral nanostructures dressed by circularly polarized
photons.Comment: 4 pages; 1 figure; published versio
How to suppress the backscattering of conduction electrons?
It is shown theoretically that the strong coupling of electrons to a
high-frequency electromagnetic field results in the nulling of electron
backscattering within the Born approximation. The conditions of the effect
depend only on field parameters and do not depend on concrete form of
scattering potential. As a consequence, this phenomenon is of universal
physical nature and can take place in various conducting systems. Since the
suppression of electron backscattering results in decreasing electrical
resistance, the solved quantum-mechanical problem opens a new way to control
electronic transport properties of conductors by a laser-generated field.
Particularly, the elaborated theory is applicable to nanostructures exposed to
a strong monochromatic electromagnetic wave.Comment: Published versio
Aharonov-Bohm effect for excitons in a semiconductor quantum ring dressed by circularly polarized light
We show theoretically that the strong coupling of circularly polarized
photons to an exciton in ring-like semiconductor nanostructures results in
physical nonequivalence of clockwise and counterclockwise exciton rotations in
the ring. As a consequence, the stationary energy splitting of exciton states
corresponding to these mutually opposite rotations appears. This excitonic
Aharonov-Bohm effect depends on the intensity and frequency of the circularly
polarized field and can be detected in state-of-the-art optical experiments.Comment: Published versio
Structure of surface electronic states in strained mercury telluride
We present the theory describing the various surface electronic states arisen
from the mixing of conduction and valence bands in a strained mercury telluride
(HgTe) bulk material. We demonstrate that the strain-induced band gap in the
Brillouin zone center of HgTe results in the surface states of two different
kinds. Surface states of the first kind exist in the small region of electron
wave vectors near the center of the Brillouin zone and have the Dirac linear
electron dispersion characteristic for topological states. The surface states
of the second kind exist only far from the center of the Brillouin zone and
have the parabolic dispersion for large wave vectors. The structure of these
surface electronic states is studied both analytically and numerically in the
broad range of their parameters, aiming to develop its systematic understanding
for the relevant model Hamiltonian. The results bring attention to the rich
surface physics relevant for topological systems.Comment: Published version. arXiv admin note: text overlap with
arXiv:1903.0457
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