We investigate effects of spin-orbit splitting on electronic transport in a spin valve consisting of a large quantum dot defined on a two-dimensional electron gas with two ferromagnetic contacts. In the presence of both structure and bulk inversion asymmetry a giant anisotropy in the spin-relaxation times has been predicted. We show how such an anisotropy affects the electronic transport proper...

We have measured the full counting statistics of current fluctuations in a semiconductor quantum dot (QD) by real-time detection of single electron tunneling with a quantum point contact. This method gives direct access to the distribution function of current fluctuations. Suppression of the second moment (related to the shot noise) and the third moment (related to the asymmetry of the distribu...

We report on a comparison between the midinfrared absorption and the photocurrent response of n-doped InAs/GaAs self-assembled quantum dots. The absorption, resonant at 160 meV, is polarized along the z growth axis of the dots. The photocurrent is dominated by a z-polarized resonance around 220 meV ~5.6 mm wavelength!. A weaker component of the photocurrent is observed for an in-plane polarized...

We consider the non-Fermi-liquid quantum critical state of the spin-S two-impurity Kondo model and its potential realization in a quantum dot device. Using conformal field theory and the numerical renormalization group, we show the critical point to be identical to that of the two-channel Kondo model with additional potential scattering, for any spin S. Distinct conductance signatures are shown...

We report polarized photoluminescence excitation spectroscopy of the negative trion in single charge-tunable quantum dots. The spectrum exhibits a p-shell resonance with polarized fine structure arising from the direct excitation of the electron spin triplet states. The energy splitting arises from the axially symmetric electron-hole exchange interaction. The magnitude and sign of the polarizat...

We report experiments on the interference through spin states of electrons in a quantum dot (QD) embedded in an Aharonov-Bohm (AB) interferometer. We have picked up a spin-pair state, for which the environmental conditions are ideally similar. The AB amplitude is traced in a range of gate voltage that covers the pair. The behavior of the asymmetry in the amplitude around the two Coulomb peaks a...

Fast quantum oscillations of a charge qubit in a double quantum dot fabricated in a Si/SiGe heterostructure are demonstrated and characterized experimentally. The measured inhomogeneous dephasing time T ∗ 2 ranges from 127 ps to 2.1 ns; it depends substantially on how the energy difference of the two qubit states varies with external voltages, consistent with a decoherence process that is domin...

We investigate the heat flow transport properties of a parallel-coupled double quantum-dot system connected to two reservoirs with temperature bias in Coulomb blockade regime. demonstrate that effects thermal rectification and negative differential conductance (NDTC) exist this analyze influences energy level difference interaction on NDTC. find can achieve high ratio NDTC when asymmetry factor...