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Negative Electron Affinity (NEA) activated GaAs photocathodes are the most popular option for generating a high current (> 1 mA) spin-polarized electron beam. Despite its popularity, a short operational lifetime is the main drawback of this…

Accelerator Physics · Physics 2024-06-12 Jai Kwan Bae , Matthew Andorf , Adam Bartnik , Alice Galdi , Luca Cultrera , Jared Maxson , Ivan Bazarov

GaAs-based photocathodes are the only viable source capable of providing spin-polarized electrons for accelerator applications. This type of photocathode requires a thin surface layer, in order to achieve negative electron affinity (NEA)…

Spin-polarized electron photoemission has been studied for GaAs/GaAs$_{1-x}$P$_x$ strained superlattice cathodes grown by gas-source molecular beam epitaxy. The superlattice structural parameters are systematically varied to optimize the…

Instrumentation and Detectors · Physics 2009-11-10 T. Maruyama , D. -A. Luh , A. Brachmann , J. E. Clendenin , E. L. Garwin , S. Harvey , J. Jiang , R. E. Kirby , C. Y. Prescott , R. Prepost , A. M. Moy

GaAs/AlGaAs quantum dots grown by in-situ droplet etching and nanohole infilling offer a combination of strong charge confinement, optical efficiency, and spatial symmetry required for polarization entanglement and spin-photon interface.…

Spin-polarized electron emission from the first superlattice photocathodes developed with strain compensation is investigated. An opposite strain in the quantum well and barrier layers is complished using an InAlGaAs/GaAsP superlattice…

A set of thin GaAs p-type negative electron affinity (NEA) photocathodes have been used to measure the yield of photoemitted electrons at high intensity excitation. The active layer thickness is 100 nm and the p-type doping ranges from…

Materials Science · Physics 2009-11-07 G. A. Mulhollan , A. V. Subashiev , J. E. Clendenin , E. L. Garwin , R. E. Kirby , T. Maruyama , R. Prepost

We report spin-polarized transient absorption for colloidal CdSe nanoplatelets as functions of thickness (2 to 6 monolayer thickness) and core/shell motif. Using electro-optical modulation of co- and cross-polarization pump-probe…

We demonstrate that photoemission properties of GaAs photocathodes (PCs) can be altered by surface acoustic waves (SAWs) generated on the PC surface due to dynamical piezoelectric fields of SAWs. Simulations with COMSOL indicate that…

Applied Physics · Physics 2019-03-26 Boqun Dong , Andrei Afanasev , Rolland P. Johnson , Mona E. Zaghloul

A new type of negative electron affinity (NEA) photocathode based on GaAs nanopillar array (NPA) Mie-type resonators was demonstrated for the first time. For visible wavelengths, the Mie resonances in GaAs NPA reduced light reflectivity to…

Magnetic molecules deposited on surfaces are a promising platform to individually address and manipulate spins. Long spin excitation lifetimes are necessary to utilize them in quantum information processing and data storage. Normally,…

Mesoscale and Nanoscale Physics · Physics 2022-08-24 Katerina Vaxevani , Jingcheng Li , Stefano Trivini , Jon Ortuzar , Danilo Longo , Dongfei Wang , Jose Ignacio Pascual

A semiclassical Monte Carlo approach is adopted to study the multivalley spin depolarization of drifting electrons in a doped n-type GaAs bulk semiconductor, in a wide range of lattice temperature ($40<T_L<300$ K) and doping density…

Statistical Mechanics · Physics 2011-12-20 Stefano Spezia , Dominique Persano Adorno , Nicola Pizzolato , Bernardo Spagnolo

The dynamic polarization of nuclear spins by photoexcited electrons is studied in a high quality GaAs/AlGaAs quantum well. We find a surprisingly high efficiency of the spin transfer from the electrons to the nuclei as reflected by a…

Mesoscale and Nanoscale Physics · Physics 2017-11-15 R. W. Mocek , V. L. Korenev , M. Bayer , M. Kotur , R. I. Dzhioev , D. O. Tolmachev , G. Cascio , K. V. Kavokin , D. Suter

We investigate the electron spin dephasing in the presence of spin phase recovering by a serried $\pi$-pulse sequence in $n$-type (001) GaAs quantum wells in a wide range of temperature and density regimes. Our numerical calculation is…

Mesoscale and Nanoscale Physics · Physics 2012-05-15 K. Shen , M. W. Wu

III-V semiconductor nanolight sources with deep-subwavelength dimensions ($<<$1 ${\mu}$m) are essential for miniaturized photonic devices such as nanoLEDs and nanolasers. However, these nanoscale emitters suffer from substantial…

Spin dephasing via the spin-orbit interaction (SOI) is a major mechanism limiting the electron spin lifetime in III-V zincblende quantum wells. The dephasing can be suppressed in GaAs(111) quantum wells by applying an electric field. The…

Mesoscale and Nanoscale Physics · Physics 2019-03-25 A. Hernández-Mínguez , K. Biermann , R. Hey , P. V. Santos

Optically addressable spins are actively investigated in quantum communication, processing and sensing. Optical and spin coherence lifetimes, which determine quantum operation fidelity and storage time, are often limited by spin-spin…

To establish a correlation between the spin diffusion, the spin lifetime, and the electron density, we study, employing time-resolved magneto-optical Kerr effect microscopy, the spin polarization evolution in low-dimensional GaAs…

Mesoscale and Nanoscale Physics · Physics 2022-08-17 S. Anghel , A. V. Poshakinskiy , K. Schiller , G. Yusa , T. Mano , T. Noda , M. Betz

Time resolved spin-polarized electron photoemission spectra are investigated as a function of excitation pulse energy for the heterostructures with a single strained layer and with a strained-well superlattice. At an average current…

Materials Science · Physics 2007-05-23 K. Aulenbacher , A. V. Subashiev , V. Tioukine , D. Bender , Yu. P. Yashin

The spin relaxation time of electrons in GaAs and GaN are determined with a model that includes momentum scattering by phonons and ionized impurities, and spin scattering by the Elliot-Yafet, D'yakonov-Perel, and Bir-Aronov-Pikus…

Materials Science · Physics 2009-11-10 S. Krishnamurthy , N. Newman , M. van Schilfgaarde

Combining highly coherent spin control with efficient light-matter coupling offers great opportunities for quantum communication and networks, as well as quantum computing. Optically active semiconductor quantum dots have unparalleled…

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