6,376 research outputs found
Fano effect and Kondo effect in quantum dots formed in strongly coupled quantum wells
We present lateral transport measurements on strongly, vertically coupled
quantum dots formed in separate quantum wells in a GaAs/AlGaAs heterostructure.
Coulomb oscillations are observed forming a honeycomb lattice consistent with
two strongly coupled dots. When the tunnel barriers in the upper well are
reduced we observe the Fano effect due to the interfering paths through a
resonant state in the lower well and a continuum state in the upper well. In
both regimes an in plane magnetic field reduces the coupling between the wells
when the magnetic length is comparable to the center to center separation of
the wells. We also observe the Kondo effect which allows the spin states of the
double dot system to be probed.Comment: 4 pages, 5 figure
Sensitivity of the magnetic state of a spin lattice on itinerant electron orbital phase
Spatially extended localized spins can interact via indirect exchange
interaction through Friedel oscillations in the Fermi sea. In arrays of
localized spins such interaction can lead to a magnetically ordered phase.
Without external magnetic field such a phase is well understood via a
"two-impurity" Kondo model. Here we employ non-equilibrium transport
spectroscopy to investigate the role of the orbital phase of conduction
electrons on the magnetic state of a spin lattice. We show experimentally, that
even tiniest perpendicular magnetic field can influence the magnitude of the
inter-spin magnetic exchange.Comment: To be published in PhysicaE EP2DS proceedin
Van der Waals Excluded Volume Model of Multicomponent Hadron Gas
A generalization of the Van der Waals excluded volume procedure for the
multicomponent hadron gas is proposed. The derivation is based on the grand
canonical partition function for the system of particles of several species
interacting by hard core potentials. The obtained formulae for thermodynamical
quantities are consistent with underlying principles of statistical mechanics
as well as with thermodynamical identities. The model can be applied to the
analysis of experimental data for particle number ratios in relativistic
nucleus-nucleus collisions.Comment: 8 page
Probing spin-charge separation in a Tomonaga-Luttinger liquid
In a one-dimensional (1D) system of interacting electrons, excitations of
spin and charge travel at different speeds, according to the theory of a
Tomonaga-Luttinger Liquid (TLL) at low energies. However, the clear observation
of this spin-charge separation is an ongoing challenge experimentally. We have
fabricated an electrostatically-gated 1D system in which we observe spin-charge
separation and also the predicted power-law suppression of tunnelling into the
1D system. The spin-charge separation persists even beyond the low-energy
regime where the TLL approximation should hold. TLL effects should therefore
also be important in similar, but shorter, electrostatically gated wires, where
interaction effects are being studied extensively worldwide.Comment: 11 pages, 4 PDF figures, uses scicite.sty, Science.bs
- …