相关论文: Spin polarized photocurrent from quantum dots

We use the spin-polarized excitons in a single quantum dot to design optical controls for basic operations in quantum computing. We examine the ultrafast nonlinear optical processes required and use the coherent nonlinear optical responses…

It has been predicted recently that an electron beam can be polarized when it flows adiabatically through a quantum point contact in a system with spin-orbit interaction. Here, we show that a simple transverse electron focusing setup can be…

We investigate real-time dynamics of spin-polarized current in a quantum dot coupled to ferromagnetic leads in both parallel and antiparallel alignments. While an external bias voltage is taken constant in time, a gate terminal,…

We investigate the spin-resolved electron dynamics in a double quantum dot driven by ultrafast asymmetric electromagnetic pulses. Using a analytical model we show that applying an appropriate pulse sequence allows to control coherently the…

We report on time-resolved ultrafast optical spectroscopy study of the topological insulator (TI) Bi$_2$Se$_3$. We unravel that a net spin polarization can not only be generated using circularly polarized light via interband transitions…

As is well known the absorption of circularly polarized light in semiconductors results in optical orientation of electron spins and helicity-dependent electric photocurrent, and the absorption of linearly polarized light is accompanied by…

We investigate theoretically the spin splitting of the exciton states in semiconductor coupled quantum dots (CQDs) containing a single magnetic ion. We find that the spin splitting can be switched on/off in the CQDs \textit{via} the…

We suggest a new spin orientation mechanism for localized electrons: $dynamic~electron~spin~polarization~provided~by~nuclear~spin~fluctuations$. The angular momentum for the electrons is gained from the nuclear spin system via the hyperfine…

Optical absorption of circularly polarized light is well known to yield an electron spin polarization in direct band gap semiconductors. We demonstrate that electron spins can even be generated with high efficiency by absorption of linearly…

To date, optical orientation of free-carrier spins and spin currents have been achieved by circularly polarized light, while the linearly polarized light has been used for optical alignment of electron momenta. Here we show that, in…

We present a quantum mechanical theory of optically induced dynamic nuclear polarization applicable to quantum dots and other interacting spin systems. The exact steady state of the optically driven coupled electron-nuclear system is…

We present a proposal for a fully electrically controllable quantum dot based spin current injector. The device consists of a quantum dot that is strongly coupled to a ferromagnetic electrode on one side and weakly coupled to a nonmagnetic…

We show theoretically that entangled photon pairs can be produced on demand through the biexciton decay of a quantum dot strongly coupled to the modes of a photonic crystal. The strong coupling allows to tune the energy of the mixed…

It is shown that, for appropriate values of electron energy, the silicene dot can work as a controllable spin polarizer. The spin polarizer can polarize the spin of transmitted electrons from nearly pure down to nearly pure up by changing…

We report optical pumping of neutral quantum dots leading to nuclear spin alignment with direction insensitive to polarization and wavelength of light. Measurements of photoluminescence of both "dark" and "bright" excitons in single dots…

The photon spin is an important resource for quantum information processing as is the electron spin in spintronics. However, for subwavelength confined optical excitations, polarization as a global property of a mode cannot be defined.…

The spin-flip rate that couples dark and bright excitons in self-assembled quantum dots is obtained from time-resolved spontaneous emission measurements in a modified local density of optical states. Employing this technique, we can…

We investigate the effect of spin-orbit interaction on the intra- and interdot particle dynamics of a double quantum dot under ac electric fields. The former is modeled as an effective ac magnetic field that produces electric-dipole spin…

We theoretically study direct current generation in a quantum spin chain induced by spinon excitations by light irradiation. We consider a s=1/2 1D antiferromagnetic XXZ model with magnetoelectric coupling that describes multiferroics with…

We demonstrate a one to one correspondence between the polarization state of a light pulse tuned to neutral exciton resonances of single semiconductor quantum dots and the spin state of the exciton that it photogenerates. This is…