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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…

Mesoscale and Nanoscale Physics · Physics 2017-02-15 J. Waetzel , A. S. Moskalenko , J. Berakdar

We present full atomistic calculations of the spin-flip time (T$_{1}$) of electrons and holes mediated by acoustic phonons in self-assembled In$_{1-x}$Ga$_x$As/GaAs quantum dots at zero magnetic field. At low magnetic field, the first-order…

Materials Science · Physics 2015-05-20 Hai Wei , Ming Gong , G-C Guo , Lixin He

We have investigated the spin preparation efficiency by optical pumping of individual Mn atoms embedded in CdTe/ZnTe quantum dots. Monitoring the time dependence of the intensity of the fluorescence during the resonant optical pumping…

Mesoscale and Nanoscale Physics · Physics 2012-06-18 C. Le Gall , R. S. Kolodka , C. Cao , H. Boukari , H. Mariette , J. Fernández-Rossier , L. Besombes

We consider a mechanism of spin decay for an electron spin in a quantum dot due to coupling to a nearby quantum point contact (QPC) with and without an applied bias voltage. The coupling of spin to charge is induced by the spin-orbit…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Massoud Borhani , Vitaly N. Golovach , Daniel Loss

We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the…

Other Condensed Matter · Physics 2009-11-11 C. Calero , E. M. Chudnovsky , D. A. Garanin

The use of single electron spins in quantum dots as qubits requires detailed knowledge about the processes involved in their initialization and operation as well as their relaxation and decoherence. In optical schemes for such spin qubits,…

Mesoscale and Nanoscale Physics · Physics 2024-02-19 Eric Kleinherbers , Hendrik Mannel , Jens Kerski , Martin Geller , Axel Lorke , Jürgen König

We consider the initialization of the spin-state of a single electron trapped in a self-assembled quantum dot via optical pumping of a trion level. We show that with a magnetic field applied perpendicular to the growth direction of the dot,…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. Emary , Xiaodong Xu , D. G. Steel , S. Saikin , L. J. Sham

We report on the local control of the transition frequency of a spin-$1/2$ encoded in two Rydberg levels of an individual atom by applying a state-selective light shift using an addressing beam. With this tool, we first study the spectrum…

Spin is a fundamental property of all elementary particles. Classically it can be viewed as a tiny magnetic moment, but a measurement of an electron spin along the direction of an external magnetic field can have only two outcomes: parallel…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. M. Elzerman , R. Hanson , L. H. Willems van Beveren , B. Witkamp , L. M. K. Vandersypen , L. P. Kouwenhoven

We advance spin noise spectroscopy to the ultimate limit of single spin detection. This technique enables the measurement of the spin dynamic of a single heavy hole localized in a flat (InGa)As quantum dot. Magnetic field and light…

Mesoscale and Nanoscale Physics · Physics 2014-04-15 Ramin Dahbashi , Jens Hübner , Fabian Berski , Klaus Pierz , Michael Oestreich

We investigate the electron and hole spin relaxation in an ensemble of self-assembled InAs/In$_{0.53}$Al$_{0.24}$Ga$_{0.23}$As/InP quantum dots with emission wavelengths around $1.5$~$\mu$m by pump-probe Faraday rotation spectroscopy.…

Mesoscale and Nanoscale Physics · Physics 2019-01-01 A. V. Mikhailov , V. V. Belykh , D. R. Yakovlev , P. S. Grigoryev , J. P. Reithmaier , M. Benyoucef , M. Bayer

Ability to read-out the state of a single confined spin lies at the heart of solid-state quantum information processing. While all-optical spin measurements using Faraday rotation has been successfully implemented in ensembles of…

Quantum Physics · Physics 2015-06-26 Mete Atature , Jan Dreiser , Antonio Badolato , Atac Imamoglu

We demonstrate the suppression of nuclear spin fluctuations in an InAs quantum dot and measure the timescales of the spin narrowing effect. By initializing for tens of milliseconds with two continuous wave diode lasers, fluctuations of the…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Bo Sun , Colin Ming Earn Chow , Duncan G. Steel , Allan S. Bracker , Daniel Gammon , L. J. Sham

The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to…

The intrinsic fluctuations of electron spins in semiconductors and atomic vapors generate a small, randomly-varying "spin noise" that can be detected by sensitive optical methods such as Faraday rotation. Recent studies have demonstrated…

We present a method of obtaining information about spin lifetimes in quantum dots from measurements of electrical transport. The dot is under resonant microwave irradiation and at temperatures comparable to or larger than the Zeeman energy.…

Mesoscale and Nanoscale Physics · Physics 2009-01-12 J. Wabnig , B. W. Lovett , J. H. Jefferson , G. A. D. Briggs

We investigate the longitudinal spin relaxation arising due to spin-flip transitions accompanied by phonon emission in quantum dots where the strength of the Rashba spin-orbit coupling is a random function of the lateral (in-plane)…

Disordered Systems and Neural Networks · Physics 2009-11-11 E. Ya. Sherman , D. J. Lockwood

Two-electron charged self-assembled quantum dot molecules exhibit a decoherence-avoiding singlet-triplet qubit subspace and an efficient spin-photon interface. Here, we demonstrate that the cycling transitions originating from auxiliary…

Mesoscale and Nanoscale Physics · Physics 2015-09-15 Y. L. Delley , M. Kroner , S. Faelt , W. Wegscheider , A. İmamoğlu

The temperature dependence of electron spin coherence in singly negatively charged (In,Ga)As/GaAs quantum dots is studied by time-resolved Faraday rotation. The decoherence time T2 is constant on a microsecond scale for temperatures below…

Materials Science · Physics 2008-07-14 F. G. G. Hernandez , A. Greilich , F. Brito , M. Wiemann , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer

Electron states in a inhomogeneous Ge/Si quantum dot array with groups of closely spaced quantum dots were studied by conventional continuous wave ($cw$) ESR and spin-echo methods. We find that the existence of quantum dot groups allows to…

Mesoscale and Nanoscale Physics · Physics 2014-12-23 A. F. Zinovieva , N. P. Stepina , A. I. Nikiforov , A. V. Nenashev , A. V. Dvurechenskii , L. V. Kulik , N. A. Sobolev , M. C. Carmo