Triplet–singlet spin relaxation via nuclei in a double quantum dot

The spin of a confined electron, when oriented originally in some direction, will lose memory of that orientation after some time. Physical mechanisms leading to this relaxation of spin memory typically involve either coupling of the electron spin to its orbital motion or to nuclear spins. Relaxation of confined electron spin has been previously measured only for Zeeman or exchange split spin states, where spin-orbit effects dominate relaxation; spin flips due to nuclei have been observed in optical spectroscopy studies. Using an isolated GaAs double quantum dot defined by electrostatic gates and direct time domain measurements, we investigate in detail spin relaxation for arbitrary splitting of spin states. Here we show that electron spin flips are dominated by nuclear interactions and are slowed by several orders of magnitude when a magnetic field of a few millitesla is applied. These results have significant implications for spin-based information processing.

[1]  B. Sapoval,et al.  Low field electron-nuclear spin coupling in gallium arsenide under optical pumping conditions , 1977 .

[2]  K. Schulten,et al.  Semiclassical description of electron spin motion in radicals including the effect of electron hopping , 1978 .

[3]  F. Stern,et al.  Electronic properties of two-dimensional systems , 1982 .

[4]  Weimann,et al.  Electrical detection of nuclear magnetic resonance in GaAs-AlxGa1-xAs heterostructures. , 1988, Physical review letters.

[5]  West,et al.  N-electron ground state energies of a quantum dot in magnetic field. , 1993, Physical review letters.

[6]  Ritchie,et al.  Measurements of Coulomb blockade with a noninvasive voltage probe. , 1993, Physical review letters.

[7]  Kouwenhoven,et al.  Local dynamic nuclear polarization using quantum point contacts. , 1994, Physical review letters.

[8]  Spontaneous emission spectrum in double quantum dot devices , 1998, Science.

[9]  D. DiVincenzo,et al.  Quantum computation with quantum dots , 1997, cond-mat/9701055.

[10]  Yuli V. Nazarov,et al.  Spin relaxation in semiconductor quantum dots , 1999, cond-mat/9907367.

[11]  Nucleus-mediated spin-flip transitions in GaAs quantum dots , 2001, cond-mat/0104148.

[12]  Optical manipulation of nuclear spin by a two-dimensional electron gas. , 2000, Physical review letters.

[13]  S. Tarucha,et al.  Allowed and forbidden transitions in artificial hydrogen and helium atoms , 2002, Nature.

[14]  A. Khaetskii,et al.  Electron spin decoherence in quantum dots due to interaction with nuclei. , 2002, Physical review letters.

[15]  Electron spin relaxation by nuclei in semiconductor quantum dots , 2002, cond-mat/0202271.

[16]  S. Tarucha,et al.  Current Rectification by Pauli Exclusion in a Weakly Coupled Double Quantum Dot System , 2002, Science.

[17]  S. Sarma,et al.  Theory of nuclear-induced spectral diffusion: Spin decoherence of phosphorus donors in Si and GaAs quantum dots , 2002, cond-mat/0211567.

[18]  P. Matagne,et al.  Experiments And Simulations On A Few‐Electron Quantum Dot Circuit With Integrated Charge Read‐Out , 2002, cond-mat/0212489.

[19]  K. Klitzing,et al.  Gate-voltage control of spin interactions between electrons and nuclei in a semiconductor , 2003 .

[20]  S. Tarucha,et al.  Nuclear-spin-induced oscillatory current in spin-blockaded quantum dots. , 2003, Physical review letters.

[21]  L. Vandersypen,et al.  Single-shot read-out of an individual electron spin in a quantum dot , 2004, Nature.

[22]  Dieter Schuh,et al.  Optically programmable electron spin memory using semiconductor quantum dots , 2004, Nature.

[23]  Hyperfine interaction in a quantum dot: Non-Markovian electron spin dynamics , 2004, cond-mat/0405676.

[24]  Keeley A. Crockett,et al.  Differential charge sensing and charge delocalization in a tunable double quantum dot. , 2003, Physical review letters.

[25]  Daniel Loss,et al.  Phonon-Induced Decay of the Electron Spin in Quantum Dots , 2004 .

[26]  A. Gossard,et al.  Manipulation of a single charge in a double quantum dot. , 2004, Physical review letters.

[27]  Y. Hirayama,et al.  Spin degree of freedom in the nu=1 bilayer electron system investigated by nuclear spin relaxation. , 2004, Physical review letters.

[28]  A. Gossard,et al.  Singlet-triplet spin blockade and charge sensing in a few-electron double quantum dot , 2004, cond-mat/0410679.

[29]  Xuedong Hu,et al.  Spin quantum computation in silicon nanostructures , 2005 .

[30]  Optical pumping of the electronic and nuclear spin of single charge-tunable quantum dots. , 2004, Physical review letters.

[31]  A. Gossard,et al.  Pulsed-gate measurements of the singlet-triplet relaxation time in a two-electron double quantum dot , 2004, cond-mat/0412048.