Related papers: Dipole-like dynamical nuclear spin polarization ar…

We theoretically investigate dynamic nuclear spin polarization in a self-assembled quantum dot pumped optically by two laser beams. With the assumption that a noncollinear interaction between the hole spin and nuclear spins leads to nuclear…

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 have developed a method for electrical polarization of nuclear spins in quantum Hall systems. In a breakdown regime of odd-integer quantum Hall effect (QHE), excitation of electrons to the upper Landau subband with opposite spin polarity…

Dynamic nuclear polarization transfers spin polarization from electrons to nuclei. We have achieved this by a new method, simultaneously exciting transitions of electronic and nuclear spins. The efficiency of this technique improves with…

We investigate dynamic nuclear polarization in quantum point contacts (QPCs) in the integer and fractional quantum Hall regimes. Following the application of a dc bias, fractional plateaus in the QPC shift symmetrically about half filling…

We investigate the dynamic nuclear polarization from the hyperfine interaction between nonequilibrium electronic spins and nuclear spins coupled to them in semiconductor nanostructures. We derive the time and position dependence of the…

We polarize nuclear spins in a GaAs double quantum dot by controlling two-electron spin states near the anti-crossing of the singlet (S) and m_S=+1 triplet (T+) using pulsed gates. An initialized S state is cyclically brought into resonance…

We present an experimental study of the dynamics underlying the buildup and decay of dynamical nuclear spin polarization in a single semiconductor quantum dot. Our experiment shows that the nuclei can be polarized on a time scale of a few…

Repeated injection of spin polarized carriers in a quantum dot leads to the polarization of nuclear spins, a process known as dynamic nuclear spin polarization (DNP). Here, we report the first observation of p-shell carrier assisted DNP in…

We investigate the dynamic nuclear polarization process by frequently injecting polarized electron spins into a quantum dot. Due to the suppression of the direct dipolar and indirect electron-mediated nuclear spin interactions, by the…

A highly asymmetric dynamic nuclear spin pumping is observed in a single self assembled InGaAs quantum dot subject to resonant optical pumping of the neutral exciton transition leading to a large maximum polarization of 54%. This dynamic…

We consider the dynamic nuclear spin polarization (DNP) using two electrons in a double quantum dot in presence of external magnetic field and spin-orbit interaction, in various schemes of periodically repeated sweeps through the S-T+…

Small differential conductance oscillations as a function of source-drain bias were observed and systematically studied in an asymmetric quantum point contact (QPC). These oscillations become significantly suppressed in a small in-plane…

The interplay of optical driving and hyperfine interaction between an electron confined in a quantum dot and its surrounding nuclear spin environment produces a range of interesting physics such as mode-locking. In this work, we go beyond…

The appearance and evolution of an anomalous conductance plateau at 0.4 (in units of 2e2/h) in an In0.52Al0.48As/InAs quantum point contact (QPC), in the presence of lateral spin-orbit coupling, has been studied at T=4.2K as a function of…

In this paper, I present a simple method of obtaining spin-polarised current from a QPC with a large Rashba interaction. The origin of this spin polarisation is the adiabatic evolution of spin "up" of the first QPC sub-band, into spin…

We study the effect of bias voltage on the nuclear spin polarization of a ballistic wire, which contains electrons and nuclei interacting via hyperfine interaction. In equilibrium, the localized nuclear spins are helically polarized due to…

We study the spin dynamics in charged quantum dots in the situation where the resident electron is coupled to only about 200 nuclear spins and where the electron spin splitting induced by the Overhauser field does not exceed markedly the…

The central-spin problem, in which an electron spin interacts with a nuclear spin bath, is a widely studied model of quantum decoherence. Dynamic nuclear polarization (DNP) occurs in central spin systems when electronic angular momentum is…

The dynamics of the coupled electron-nuclear spin system is studied in an ensemble of singly-charged (In,Ga)As/GaAs quantum dots (QDs) using periodic optical excitation at 1 GHz repetition rate. In combination with the electron-nuclei…