相关论文: Nonequilibrium nuclear-electron spin dynamics in s…

The concept of nuclear spin temperature has been a cornerstone of the theory of dynamic nuclear spin polarization by electrons in various semiconductor structures for decades. Still, it is not always applicable to strongly localized…

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…

We study theoretically the cooling of an ensemble of nuclear spins coupled to the spin of a localized electron in a quantum dot. We obtain a master equation for the state of the nuclear spins interacting with a sequence of polarized…

We propose to use the spin-blockade regime in double quantum dots to reduce nuclear spin polarization fluctuations in analogy with optical Doppler cooling. The Overhauser shift brings electron levels in and out of resonance, creating…

We theoretically study the nuclear spin dynamics driven by electron transport and hyperfine interaction in an electrically-defined double quantum dot (DQD) in the Pauli-blockade regime. We derive a master-equation-based framework and show…

Semiconductor quantum dots provide a spin-coupled system of an electron and nuclei via enhanced hyperfine interaction. We showed that the nuclear spin polarization in single quantum dots can have three stable branches under a longitudinal…

We study electron spin decoherence in a two-electron double quantum dot due to the hyperfine interaction, under spin-echo conditions as studied in recent experiments. We develop a semi-classical model for the interaction between the…

We report manifestly nonlinear dependence of quantum dot nuclear spin polarization on applied magnetic fields. Resonant absorption and emission of circularly polarized radiation pumps the resident quantum dot electron spin, which in turn…

The main source of decoherence for an electron spin confined to a quantum dot is the hyperfine interaction with nuclear spins. To analyze this process theoretically we diagonalize the central spin Hamiltonian in the high magnetic B-field…

Relaxation of conduction electron spins in a semiconductor owing to the hyperfine interaction with spin-1/2 nuclei, in zero applied magnetic field, is investigated. We calculate the electron spin relaxation time scales, in order to evaluate…

We demonstrate that non-equilibrium electrons in thin nonmagnetic semiconductor layers or quantum dots can be fully spin polarized by means of simultaneous electrical spin injection and extraction. The complete spin polarization is achieved…

Understanding fully the dynamics of coupled electron-nuclear spin systems, which are important for the development of long-lived qubits based on solid-state systems, remains a challenge. We show that in a singly charged semiconductor…

We propose a new mechanism for polarizing nuclear spins in quantum dots, based on periodic modulation of the hyperfine coupling by electric driving at the electron spin resonance frequency. Dynamical nuclear polarization results from…

We introduce a method for solving the problem of an externally controlled electron spin in a quantum dot interacting with host nuclei via the hyperfine interaction. Our method accounts for generalized (non-unitary) evolution effected by…

The nature of the nano-scale environment presents a major challenge for solid-state implementation of spin-based qubits. In this work, a single electron spin in an optically pumped nanometer-sized III-V semiconductor quantum dot is used to…

Early experiments on spin-blockaded double quantum dots revealed surprising robust, large-amplitude current oscillations in the presence of a static (dc) source-drain bias [see e.g. K. Ono, S. Tarucha, Phys. Rev. Lett. 92, 256803 (2004)].…

Hyperfine interaction of electron spins with nuclear spins, in coupled double quantum dots is studied. Results of successive electron spin measurements exhibit bunching due to correlations induced via the nuclear spins. Further nuclear…

We have studied theoretically the electron spin relaxation in semiconductor quantum dots via interaction with nuclear spins. The relaxation is shown to be determined by three processes: (i) -- the precession of the electron spin in the…

The control of nuclear spins in quantum dots is essential to explore their many-body dynamics and exploit their prospects for quantum information processing. We present a unique combination of dynamic nuclear spin polarization and…

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…