A new mechanism of electric dipole spin resonance: hyperfine coupling in quantum dots

Abstract

A recently discovered mechanism of electric dipole spin resonance, mediated by the hyperfine interaction, is investigated experimentally and theoretically. The effect is studied using a spin-selective transition in a GaAs double quantum dot. The resonant frequency is sensitive to the instantaneous hyperfine effective field, revealing a nuclear polarization created by driving the resonance. A device incorporating a micromagnet exhibits a magnetic field difference between dots, allowing electrons in either dot to be addressed selectively. An unexplained additional signal at half the resonant frequency is presented.

Electric-dipole-induced spin resonance in a lateral double quantum dot incorporating two single-domain nanomagnets

“…6d. Such a behavior can be explained in terms of higher order harmonics generation and has also been observed to such a high order in comparable EDSR experiments in an InAs nanowire based double QD [27] and to second order in another GaAs based double QD [28]. A related example of higher order harmonics generation are Landau-ZenerStückelberg-Majorana interference oscillations [29,30].…”

Mechanism of half-frequency electric dipole spin resonance in double quantum dots: Effect of nonlinear charge dynamics inside the singlet manifold

“…15. According to the above assumptions, oscillations of electronic density parametrized above in terms of the dipole moments r(t) drive EDSR through the B(r) mechanism and in this way affect the efficiency of the Pauli blockade.…”

“…6 of Ref. 15 both the linear and quadratic responses are split, at least into two components (visibility of the components is reduced by fluctuations of the nuclear bath). At B ≈ 100 mT, where this splitting is best seen, it is ∼10% of the Zeeman energy.…”

“…However, more recently Laird et al 15 reported intensive EDSR in GaAs double quantum dots (DQDs) at the halffrequency ω = 1 2 ω B observed side by side with the EDSR at the basic frequency ω = ω B ; 15 it was detected by breaking Pauli blockade. They emphasized that a "half-frequency response is as far as we know unprecedented in spin resonance."…”

“…To keep connection to the data of Ref. 15, I concentrate on the vicinity of the charge balance line separating the stability regions of (0,2) and (1,1) singlet states that are displayed schematically in Fig. 1.…”