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The phonon-induced spin relaxation in a two-dimensional quantum dot embedded inside a semiconductor slab is investigated theoretically. An enhanced relaxation rate is found due to the phonon van Hove singularities. Oppositely, a vanishing…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Y. Y. Liao , Y. N. Chen , D. S. Chuu , T. Brandes

We study the spin relaxation in an interacting two--dimensional electron gas in a strong magnetic field for the case that the electron density is close to filling just one Landau sub--level of one spin projection, i.e., for filling factor…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 W. Apel , Yu. A. Bychkov

Pure dephasing of an exciton in a small quantum dot by optical and acoustic phonons is calculated using the ``independent boson model''. Considering the case of zero temperature the dephasing is shown to be only partial which manifests…

Condensed Matter · Physics 2009-11-07 E. Pazy

We directly measure the hole spin lifetime in ferromagnetic GaMnAs via time- and polarization-resolved spectroscopy. Below the Curie temperature Tc, an ultrafast photoexcitation with linearly-polarized light is shown to create a…

Materials Science · Physics 2015-04-10 Aaron Patz , Tianqi Li , Xinyu Liu , Jacek K. Furdyna , Ilias E. Perakis , Jigang Wang

We develop a theory of spin relaxation in Zeeman-splitted superconducting films at low temperatures. A new mechanism of spin relaxation, specific only for Zeeman-splitted superconductors is proposed. It can explain the extremely high spin…

Superconductivity · Physics 2015-06-23 I. V. Bobkova , A. M. Bobkov

In silicon quantum dots (QDs), at a certain magnetic field commonly referred to as the "hot spot", the electron spin relaxation rate (T_1^(-1)) can be drastically enhanced due to strong spin-valley mixing. Here, we experimentally find that…

We estimate the triplet-singlet relaxation rate due to spin-orbit coupling assisted by phonon emission in weakly-confined quantum dots. Our results for two and four electrons show that the different triplet-singlet relaxation trends…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Juan I. Climente , Andrea Bertoni , Guido Goldoni , Massimo Rontani , Elisa Molinari

In this paper we show that it is possible to switch the spin polarization of the photocurrent signal obtained from a single self-assembled quantum dot photodiode under the effect of elliptically polarized light by just increasing the light…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 J. M. Villas-Boas , Sergio E. Ulloa , A. O. Govorov

Circularly polarized optical excitation is used to demonstrate the efficient injection of spin-polarized excitons to individual self-assembled CdSe quantum dots in ZnSe barrier. The exciton spin-transfer is studied by means of…

Mesoscale and Nanoscale Physics · Physics 2014-08-14 T. Smoleński , W. Pacuski , M. Goryca , M. Nawrocki , A. Golnik , P. Kossacki

The quantum-jump approach is used for a theoretical description of resonance luminescence from a {\em single} semiconductor quantum dot in contact with its solid-state environment. For continuous excitation of the single-exciton groundstate…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Ulrich Hohenester

We have studied the spin dynamics of a dense two-dimensional electron gas confined in a GaAs/AlGaAs triple quantum well by using time-resolved Kerr rotation and resonant spin amplification. Strong anisotropy of the spin relaxation time up…

Mesoscale and Nanoscale Physics · Physics 2017-06-28 S. Ullah , G. M. Gusev , A. K. Bakarov , F. G. G. Hernandez

We have demonstrated experimentally the manipulation of exciton and nuclear spins in a single self-assembled In$_{0.75}$Al$_{0.25}$As/Al$_{0.3}$Ga$_{0.7}$As quantum dot. The oscillation of exciton and nuclear spin polarizations were clearly…

Other Condensed Matter · Physics 2007-05-23 H. Sasakura , S. Adachi , S. Muto , S. Hirose , H. Z. Song , M. Takatsu

We report on a new approach to detect excitonic qubits in semiconductor quantum dots by observing spontaneous emissions from the relevant qubit level. The ground state of excitons is resonantly excited by picosecond optical pulses.…

Materials Science · Physics 2007-05-23 K. Kuroda , T. Kuroda , K. Watanabe , T. Mano , K. Sakoda , G. Kido , N. Koguchi

We investigate the electron spin relaxation of $n$-type InAs quantum wires by numerically solving the fully microscopic kinetic spin Bloch equations with the relevant scattering explicitly included. We find that the quantum-wire size and…

Materials Science · Physics 2009-10-03 C. Lü , H. C. Schneider , M. W. Wu

We analyse the influence of optically generated non-equilibrium phonons on the spin relaxation and effective spin temperature of an individual Cr atom inserted in a quantum dot. Using a three pulses pump-probe technique, we show that the…

Mesoscale and Nanoscale Physics · Physics 2020-02-05 V. Tiwari , K. Makita , M. Arino , M. Morita , S. Kuroda , H. Boukari , L. Besombes

Using the emission of the positively charged exciton as a probe, we analyze the dynamics of the optical pumping and the dynamics of the relaxation of a Mn spin exchange-coupled with a confined hole spin in a II-VI semiconductor quantum dot.…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 B. Varghese , H. Boukari , L. Besombes

We probe acoustic phonon mediated relaxation between tunnel coupled exciton states in an individual quantum dot molecule in which the inter-dot quantum coupling and energy separation between exciton states is continuously tuned using static…

Mesoscale and Nanoscale Physics · Physics 2007-10-10 T. Nakaoka , H. J. Krenner , E. C. Clark , M. Sabathil , M. Bichler , Y. Arakawa , G. Abstreiter , J. J. Finley

We discuss the rate of relaxation of the total spin in the two-electron droplet in the vicinity of the magnetic field driven singlet-triplet transition. The total spin relaxation is attributed to spin-orbit and electron-phonon interactions.…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 S. Dickmann , P. Hawrylak

Spins in semiconductor quantum dots are promising local quantum memories to generate polarization-encoded photonic cluster states, as proposed in the pioneering Rudolph-Lindner scheme [1]. However, harnessing the polarization degree of…

Mesoscale and Nanoscale Physics · Physics 2023-11-28 N. Coste , M. Gundin , D. Fioretto , S. E. Thomas , C. Millet , E. Medhi , M. Gundin , N. Somaschi , M. Morassi , M. Pont , A. Lemaitre , N. Belabas , O. Krebs , L. Lanco , P. Senellart

Direct phonon spin-lattice relaxation of an electron qubit bound by a donor impurity or quantum dot in SiGe heterostructures is investigated. The aim is to evaluate the importance of decoherence from this mechanism in several important…

Materials Science · Physics 2009-11-07 Charles Tahan , Mark Friesen , Robert Joynt