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Asymmetry in a three-electron double quantum dot (DQD) allows spin blockade, when spin-3/2 (quadruplet) states and spin-1/2 (doublet) states have different charge configurations. We have observed this DQD spin blockade near the (1,2)-(2,1)…

Mesoscale and Nanoscale Physics · Physics 2020-03-04 Bao-Bao Chen , Bao-Chuan Wang , Gang Cao , Hai-Ou Li , Ming Xiao , Guang-Can Guo , Hong-Wen Jiang , Xuedong Hu , Guo-Ping Guo

We analytically solve the {\it Non-Markovian} single electron spin dynamics due to hyperfine interaction with surrounding nuclei in a quantum dot. We use the equation-of-motion method assisted with a large field expansion, and find that…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Changxue Deng , Xuedong Hu

A pair of coupled dots with one electron in each dot can provide improvements in spin coherence, particularly at an electrical bias called the sweet spot, but few measurements have been performed on self-assembled dots in this regime. Here,…

Mesoscale and Nanoscale Physics · Physics 2022-02-17 Kha X. Tran , Allan S. Bracker , Michael K. Yates , Joel Q. Grim , Samuel G. Carter

In semiconductors, the T2* coherence time of a single confined spin is limited either by the fluctuating magnetic environment (via the hyperfine interaction), or by charge fluctuations (via the spin-orbit interaction). We demonstrate that…

Mesoscale and Nanoscale Physics · Physics 2012-04-13 K. M. Weiss , J. M. Elzerman , Y. L. Delley , J. Miguel-Sanchez , A. Imamoglu

Control of electron spin decoherence in contact with a mesoscopic bath of many interacting nuclear spins in an InAs quantum dot is studied by solving the coupled quantum dynamics. The nuclear spin bath, because of its bifurcated evolution…

Mesoscale and Nanoscale Physics · Physics 2011-11-09 Ren-Bao Liu , Wang Yao , L. J. Sham

Recent experiments have demonstrated quantum manipulation of two-electron spin states in double quantum dots using electrically controlled exchange interactions. Here, we present a detailed theory for electron spin dynamics in two-electron…

Mesoscale and Nanoscale Physics · Physics 2012-10-19 J. M. Taylor , J. R. Petta , A. C. Johnson , A. Yacoby , C. M. Marcus , M. D. Lukin

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

We study the decoherence of a single electron spin in an isolated quantum dot induced by hyperfine interaction with nuclei for times smaller than the nuclear spin relaxation time. The decay is caused by the spatial variation of the electron…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Alexander Khaetskii , Daniel Loss , Leonid Glazman

We consider a double quantum dot whose energy detuning is controlled by an ac electric field. We demonstrate an energy configuration for which the ac-induced current flowing through the double dot directly probes the spin-orbit anticrossing…

Mesoscale and Nanoscale Physics · Physics 2020-03-17 G. Giavaras , Yasuhiro Tokura

We perform a systematic exact diagonalization study of spin-orbit coupling effects for stationary few-electron states confined in quasi two-dimensional double quantum dots. We describe the spin-orbit-interaction induced coupling between…

Mesoscale and Nanoscale Physics · Physics 2010-06-17 M. P. Nowak , B. Szafran

We investigate the performance of dynamical decoupling methods at suppressing electron spin decoherence from a low-temperature nuclear spin reservoir in a quantum dot. The controlled dynamics is studied through exact numerical simulation,…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Wenxian Zhang , V. V. Dobrovitski , Lea F. Santos , Lorenza Viola , B. N. Harmon

Spin-orbit effects on electron-electron interaction are studied theoretically. The corrections to the Coulomb interaction of quantum well electrons induced by the spin-orbit coupling are derived. The developed theory is applied to calculate…

Mesoscale and Nanoscale Physics · Physics 2009-05-08 M. M. Glazov , V. D. Kulakovskii

Spin qubits defined in carbon nanotube quantum dots are of considerable interest for encoding and manipulating quantum information because of the long electron spin coherence times expected. However, before carbon nanotubes can find…

Mesoscale and Nanoscale Physics · Physics 2010-04-27 S. J. Chorley , G. Giavaras , J. Wabnig , G. A. C. Jones , C. G. Smith , G. A. D. Briggs , M. R. Buitelaar

We study electron-phonon interaction induced decoherence between two-electron singlet and triplet states in a semiconductor double quantum dot using a spin-boson model. We investigate the onset and time evolution of this dephasing, and…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Xuedong Hu

Spin-orbit coupling is relatively weak for electrons in bulk silicon, but enhanced interactions are reported in nanostructures such as the quantum dots used for spin qubits. These interactions have been attributed to various dissimilar…

We study exchange coupling in Si double quantum dots, which have been proposed as suitable candidates for spin qubits due to their long spin coherence times. We discuss in detail two alternative schemes which have been proposed for…

Mesoscale and Nanoscale Physics · Physics 2010-02-12 Qiuzi Li , Lukasz Cywinski , Dimitrie Culcer , Xuedong Hu , S. Das Sarma

We consider the full driven quantum dynamics of a qubit realized as spin of electron in a one-dimensional double quantum dot with spin-orbit coupling. The driving perturbation is taken in the form of a single half-period pulse of electric…

Mesoscale and Nanoscale Physics · Physics 2010-09-28 D. V. Khomitsky , E. Ya. Sherman

We review progress on the spintronics proposal for quantum computing where the quantum bits (qubits) are implemented with electron spins. We calculate the exchange interaction of coupled quantum dots and present experiments, where the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hans-Andreas Engel , L. P. Kouwenhoven , Daniel Loss , C. M. Marcus

The time evolution of spin states of two electrons interacting with a nuclear spin bath in a quantum dot system is studied. The hyperfine interaction between the electrons and the nuclear spins is modeled by an isotropic Heisenberg…

Quantum Physics · Physics 2013-07-09 D. D. Bhaktavatsala Rao , V. Ravishankar , V. Subrahmanyam

We investigate theoretically the combined effects of the electron-electron and the Rashba spin-orbit interactions on two electrons confined in quasi-one-dimensional AlInSb-based double quantum dots. We calculate the two-electron wave…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 C. L. Romano , P. I. Tamborenea , S. E. Ulloa