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We measure the relaxation rate $W \equiv T_{1}^{-1}$ of a single electron spin in a quantum dot at magnetic fields from 7 T down to 1.75 T, much lower than previously measured. At 1.75 T we find that $T_{1}$ is 170 ms. We find good…

Mesoscale and Nanoscale Physics · Physics 2009-09-29 S. Amasha , K. MacLean , Iuliana Radu , D. M. Zumbuhl , M. A. Kastner , M. P. Hanson , A. C. Gossard

The spin relaxation time due to the electron-acoustic phonon scattering in GaAs quantum dots is studied after the exact diagonalization of the electron Hamiltonian with the spin-orbit coupling. Different effects such as the magnetic field,…

Condensed Matter · Physics 2012-07-02 J. L. Cheng , M. W. Wu , C. Lü

We study spin relaxation in a two-electron quantum dot in the vicinity of the singlet-triplet crossing. The spin relaxation occurs due to a combined effect of the spin-orbit, Zeeman, and electron-phonon interactions. The singlet-triplet…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Vitaly N. Golovach , Alexander Khaetskii , Daniel Loss

We present the experimental observation of a large exchange coupling $J \approx 300$ $\mu$eV between two $^{31}$P electron spin qubits in silicon. The singlet and triplet states of the coupled spins are monitored in real time by a…

Mesoscale and Nanoscale Physics · Physics 2014-06-12 Juan P. Dehollain , Juha T. Muhonen , Kuan Y. Tan , André Saraiva , David N. Jamieson , Andrew S. Dzurak , Andrea Morello

We investigated the time dependence of two-electron spin states in a double quantum dot fabricated in an InAs nanowire. In this system, spin-orbit interaction has substantial influence on the spin states of confined electrons. Pumping…

Mesoscale and Nanoscale Physics · Physics 2009-04-30 A. Pfund , I. Shorubalko , K. Ensslin , R. Leturcq

The electron spin dynamics in (111)-oriented GaAs/AlGaAs quantum wells is studied by timeresolved photoluminescence spectroscopy. By applying an external field of 50 kV/cm a two-order of magnitude increase of the spin relaxation time can be…

Materials Science · Physics 2015-05-28 A. Balocchi , Q. H. Duong , P. Renucci , B. Liu , C. Fontaine , T. Amand , D. Lagarde , X. Marie

While electron spins in silicon heterostructures make attractive qubits, little is known about the coherence of electrons at the Si/SiO2 interface. We report spin relaxation (T1) and coherence (T2) times for mobile electrons and natural…

Materials Science · Physics 2010-11-29 S. Shankar , A. M. Tyryshkin , Jianhua He , S. A. Lyon

We study the triplet-singlet relaxation in two-electron semiconductor quantum dots. Both single dots and vertically coupled double dots are discussed. In our work, the electron-electron Coulomb interaction, which plays an important role in…

Materials Science · Physics 2007-12-18 K. Shen , M. W. Wu

We study the singlet-triplet relaxation due to the spin-orbit coupling assisted by the electron-phonon scattering in two-electron SiGe/Si/SiGe double quantum dots in the presence of an external magnetic field in either Faraday or Voigt…

Mesoscale and Nanoscale Physics · Physics 2011-08-26 L. Wang , M. W. Wu

We observe an experimental signature of the role of the phonons in spin relaxation between triplet and singlet states in a two-electron quantum dot. Using both the external magnetic field and the electrostatic confinement potential, we…

We study theoretically phonon-induced spin dynamics of two electrons confined in a self-assembled double quantum dot. We calculate the transition rates and time evolution of occupations for the spin-triplet and spin-singlet states. We…

Mesoscale and Nanoscale Physics · Physics 2020-05-13 Krzysztof Gawarecki , Paweł Machnikowski

Singlet-triplet spin blockade in a few-electron lateral double quantum dot is investigated using simultaneous transport and charge-sensing measurements. Transport from the (1,1) to the (0,2) electron occupancy states is strongly suppressed…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. C. Johnson , J. R. Petta , C. M. Marcus , M. P. Hanson , A. C. Gossard

We present a numerical study of spin relaxation in a semiclassical electron ensemble in a large ballistic quantum dot. The dot is defined in a GaAs/AlGaAs heterojunction system with a two-dimensional electron gas, and relaxation occurs due…

Mesoscale and Nanoscale Physics · Physics 2008-04-21 E. J. Koop , B. J. van Wees , C. H. van der Wal

We study the relaxation of the exciton spin (longitudinal relaxation time $T_{1}$) in single asymmetrical quantum dots due to an interplay of the short--range exchange interaction and acoustic phonon deformation. The calculated relaxation…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 E. Tsitsishvili , R. v. Baltz , H. Kalt

By operating a one-electron quantum dot (fabricated between a multielectron dot and a one-electron reference dot) as a spectroscopic probe, we study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition…

A global quantitative picture of the phonon-induced two-electron spin relaxation in GaAs double quantum dots is presented using highly accurate numerical calculations. Wide regimes of interdot coupling, magnetic field magnitude and…

Mesoscale and Nanoscale Physics · Physics 2013-02-01 Martin Raith , Peter Stano , Fabio Baruffa , Jaroslav Fabian

We present numerical results for electron spin relaxation rates for single and laterally coupled double GaAs quantum dots in a perpendicular magnetic field. As source of spin relaxation we consider hyperfine interaction with the nuclear…

Mesoscale and Nanoscale Physics · Physics 2007-12-17 Johannes Voss , Daniela Pfannkuche

Spin-orbit mediated phonon relaxation in a two-dimensional quantum dot is investigated using different confining potentials. Elliptical harmonic oscillator and cylindrical well results are compared to each other in the case of a…

Mesoscale and Nanoscale Physics · Physics 2017-10-25 C. J. Wesslén , E Lindroth

We demonstrate a coherent spin shuttle through a GaAs/AlGaAs quadruple-quantum-dot array. Starting with two electrons in a spin-singlet state in the first dot, we shuttle one electron over to either the second, third or fourth dot. We…

Mesoscale and Nanoscale Physics · Physics 2019-08-02 T. Fujita , T. A. Baart , C. Reichl , W. Wegscheider , L. M. K. Vandersypen

We have observed the Zeeman-split excited state of a spin-1/2 multi-electron Si/SiGe depletion quantum dot and measured its spin relaxation time T1 in magnetic fields up to 2 T. Using a new step-and-reach technique, we have experimentally…