Hyperfine-Mediated Gate-Driven Electron Spin Resonance

Abstract

An all-electrical spin resonance effect in a GaAs few-electron double quantum dot is investigated experimentally and theoretically. The magnetic field dependence and absence of associated Rabi oscillations are consistent with a novel hyperfine mechanism. The resonant frequency is sensitive to the instantaneous hyperfine effective field, and the effect can be used to detect and create sizable nuclear polarizations. A device incorporating a micromagnet exhibits a magnetic field difference between dots, allowing electrons in either dot to be addressed selectively.

Collective nuclear stabilization in single quantum dots by noncollinear hyperfine interaction

“…This resonant nature makes the strength of our mechanism comparable with the detrimental nuclear spin depolarization even if the non-collinear HI is weak 6,11 . The physics of our mechanism depicted above differs qualitatively from previous theories [6][7][8][9][10][11] . First, the nuclear spin flip is not accompanied by any change of the hole state, in contrast to the pair-wise electron-nuclear spin flip-flop [7][8][9][10] .…”

“…The key process of this mechanism is the flip of the nuclear spins through their non-collinear HI with the hole excited by nonresonant pumping (instead of resonant pumping 6,11 or through the isotropic contact HI with the ground state electron under resonant pumping [7][8][9][10] ). This process has a preferential direction giving rise to an antisymmetric steady-state nuclear field, which in turn drives a nonlinear feedback loop leading to efficient NS.…”

Theory of spin relaxation in two-electron laterally coupled Si/SiGe quantum dots

“…[2][3][4] In GaAs-based qubits, which are the state of the art, the essential gate operations 1, 5,6 for quantum computation 7,8 have been demonstrated. [9][10][11][12][13][14][15][16][17][18] But GaAs possesses a serious handicap for coherent spin manipulations-the nuclear spins. 19,20 Controlling this source of decoherence is of major interest and an active field of research.…”

Decoherence dynamics of a single spin versus spin ensemble

“…5,6 Also, the studies of single spins allow detailed exploration of fundamental questions related to complex quantum dynamics in spin systems. During the last few years, rapid progress in this direction leads to implementation of measurement and control of various single-spin systems, such as single electron spins localized in quantum dots, [7][8][9][10] spins of impurity centers in diamond, [11][12][13][14] or electron spins in SiO 2 ͑Refs. 15 and 16͒.…”