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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…

We demonstrate all-electrical spin generation and subsequent manipulation by two successive electric field pulses in an n-InGaAs heterostructure in a time-resolved experiment at zero external magnetic field. The first electric field pulse…

Mesoscale and Nanoscale Physics · Physics 2014-02-12 I. Stepanov , S. Kuhlen , M. Ersfeld , M. Lepsa , B. Beschoten

Electron spin coherence has been generated optically in n-type modulation doped (In,Ga)As/GaAs quantum dots (QDs) which contain on average a single electron per dot. The coherence arises from resonant excitation of the QDs by…

We find that detuning an optical pulse train from electronic transitions in quantum dots controls the direction of nuclear spin flips. The optical pulse train generates electron spins that precess about an applied magnetic field, with a…

Quantum Physics · Physics 2015-05-13 S. G. Carter , A. Shabaev , Sophia E. Economou , T. A. Kennedy , A. S. Bracker , T. L. Reinecke

The precise control of spins in semiconductor spintronic devices requires electrical means for generating spin packets with a well-defined initial phase. We demonstrate a pulsed electrical scheme that triggers the spin ensemble phase in a…

Mesoscale and Nanoscale Physics · Physics 2021-11-24 L. R. Schreiber , C. Schwark , G. Güntherodt , M. Lepsa , C. Adelmann , C. J. Palmstrøm , X. Lou , P. A. Crowell , B. Beschoten

We demonstrate methods to locally control the spin rotation of moving electrons in a GaAs channel. The Larmor frequency of optically-injected spins is modulated when the spins are dragged through a region of spin-polarized nuclei created at…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 M. E. Nowakowski , G. D. Fuchs , S. Mack , N. Samarth , D. D. Awschalom

We demonstrate optical control of the geometric phase acquired by one of the spin states of an electron confined in a charge-tunable InAs quantum dot via cyclic 2pi excitations of an optical transition in the dot. In the presence of a…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Erik D. Kim , Katherine Truex , Xiaodong Xu , Bo Sun , D. G. Steel , A. S. Bracker , D. Gammon , L. J. Sham

Time-resolved electrical spin transport is used to generate and probe spin currents in GaAs electrically. We use high bandwidth current pulses to inject phase-coherent spin packets from Fe into n-GaAs. By means of time-resolved Faraday…

A ring structure fabricated from GaAs is used to achieve interference of the net spin polarization of conduction band electrons. Optically polarized spins are split into two packets by passing through two arms of the ring in the diffusive…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Y. K. Kato , R. C. Myers , A. C. Gossard , D. D. Awschalom

We use quantum optimal control theory algorithms to design external electric fields that drive the coupled spin and orbital dynamics of an electron in a double quantum dot, subject to the spin-orbit interaction and Zeeman magnetic fields.…

Mesoscale and Nanoscale Physics · Physics 2016-02-17 J. A. Budagosky , D. V. Khomitsky , E. Ya. Sherman , Alberto Castro

We show that the electron spin polarization generated by an electrical current may have its direction controlled and magnitude amplified by periodic optical excitation. The electrical and optical spin control methods were combined and…

Mesoscale and Nanoscale Physics · Physics 2014-07-17 Felix G. G. Hernandez , Gennady M. Gusev , Askhat K. Bakarov

Using the recently reported mode locking effect we demonstrate a highly robust control of electron spin coherence in an ensemble of (In,Ga)As quantum dots during the single spin coherence time. The spin precession in a transverse magnetic…

Manipulation of single spins is essential for spin-based quantum information processing. Electrical control instead of magnetic control is particularly appealing for this purpose, since electric fields are easy to generate locally on-chip.…

Mesoscale and Nanoscale Physics · Physics 2008-03-10 K. C. Nowack , F. H. L. Koppens , Yu. V. Nazarov , L. M. K. Vandersypen

We report on spatially resolved measurements of the spin-orbit effective magnetic field in a GaAs/InGaAs quantum-well. Biased gate electrodes lead to an electric-field distribution in which the quantum-well electrons move according to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 L. Meier , G. Salis , E. Gini , I. Shorubalko , K. Ensslin

Electron spin dynamics is investigated in n-i-n GaAs/AlGaAs coupled quantum wells. The electron spin dephasing time is measured as a function of an external electrical bias under resonant excitation of the 1sHH intrawell exciton using a…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 A. V. Larionov , L. E. Golub

We suggest a new pump-probe method for studying semiconductor spin dynamics based on pumping of carrier spins by a pulse of oscillating radiofrequency (rf) magnetic field and probing by measuring the Faraday rotation of a short laser pulse.…

Mesoscale and Nanoscale Physics · Physics 2019-04-26 V. V. Belykh , D. R. Yakovlev , M. Bayer

We develop a simple method for measuring the electron spin relaxation times $T_1$, $T_2$ and $T_2^*$ in semiconductors and demonstrate its exemplary application to $n$-type GaAs. Using an abrupt variation of the magnetic field acting on…

Mesoscale and Nanoscale Physics · Physics 2020-08-05 V. V. Belykh , D. R. Yakovlev , M. Bayer

Time- and spatially-resolved Faraday rotation spectroscopy is used to measure the magnitude and direction of the momentum-dependent spin splitting in strained InGaAs epilayers. The epilayers are lattice-matched to the GaAs substrate and…

Mesoscale and Nanoscale Physics · Physics 2010-08-10 B. M. Norman , C. J. Trowbridge , J. Stephens , A. C. Gossard , D. D. Awschalom , V. Sih

The polarization of conduction electron spins due to an electrical current is observed in strained nonmagnetic semiconductors using static and time-resolved Faraday rotation. The density, lifetime, and orientation rate of the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Y. Kato , R. C. Myers , A. C. Gossard , D. D. Awschalom

We demonstrate high-fidelity reversible transfer of quantum information from the polarisation of photons into the spin-state of an electron-hole pair in a semiconductor quantum dot. Moreover, spins are electrically manipulated on a…

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