Decoherence of nuclear spins due to dipole-dipole interactions probed by resistively detected nuclear magnetic resonance

Abstract

Articles you may be interested inResistive detection of optically pumped nuclear polarization with spin phase transition peak at Landau level filling factor 2/3 Appl. Phys. Lett. 99, 112106 (2011); 10.1063/1.3640215 Features of polymer chain dynamics as revealed by intermolecular nuclear magnetic dipole-dipole interaction: Model calculations and field-cycling NMR relaxometry J. Chem. Phys. 132, 094903 (2010); 10.1063/1.3336832Temperature dependence of the resistively detected electron spin resonance signals in a wide parabolic quantum well AIP Conf.We study decoherence of nuclear spins in a GaAs quantum well structure using resistively detected nuclear magnetic resonance. The transverse decoherence time T 2 of 75 As nuclei is estimated from Rabi-type coherent oscillations as well as by using spin-echo techniques. By analyzing T 2 obtained by decoupling techniques, we extract the role of dipole-dipole interactions as sources of decoherence in GaAs. Under the condition that the device is tilted in an external magnetic field, we exhibit enhanced decoherence induced by the change in strength of the direct dipole-dipole interactions between first nearest-neighbor nuclei. The results agree well with simple numerical calculations.

Contact Hyperfine Interactions in Semiconductor Heterostructures

“…The above scenario was confirmed by conducting measurements with the device tilted with respect to B 0 (Ota et al, 2007). 1/T 2,Rabi values of As-Ga, As-As, and As-e were 0.67, 0.76, and 1.43 ms À1 when B 0 was tilted with an angle of =32 from the perpendicular to the (100) surface as shown in Figure 24(b).…”

“…Figure 24(a) shows the oscillation without any decoupling. To decouple 75 As from 69 Ga and 71 Ga nuclei, these nuclei can be randomized by using broadband irradiation to average the inhomogeneous local field due to heteronuclear dipole coupling (Ota et al, 2007). The point-contact device allows us to decouple nuclei from the conductive electrons, since electrons in the point-contact region can be depleted during the manipulation of nuclei with an RF pulse by applying a sufficiently large negative voltage to the split gates.…”

“…The decoherence rate, 1/T 2,Rabi , to which individual mechanisms contribute, can be estimated from the above decoupling experiments (Ota et al, 2007). The respective contributions of As-Ga, As-As, and As-e to 1/T 2,Rabi are 0.28, 0.63, and 0.76 ms À1 , respectively (see the inset in Figure 24(a)).…”

Nuclear spin manipulation in semiconductor nanostructures

“…20, 21 We have further performed spin echo experiments to extract the homogeneous decoherence time in our device. 22,23 We also developed various decoupling techniques to distinguish individual decoherence mechanisms. 22,23 The creation of effective pure states and their use for quantum information processing are described in Refs.…”

Strain and origin of inhomogeneous broadening probed by optically detected nuclear magnetic resonance in a (110) GaAs quantum well

“…The experimentally evaluated strain has the same order of that induced by the lattice mismatch between GaAs and Al 0.3 Ga 0.7 As. As for the discrepancy, it might be owing to the difference of the coefficients of the thermal expansion between the epoxy and GaAs, which causes the comparable strain in a GaAs QW [25][26][27]. Therefore, it might be that the present QW sample strain was induced mainly by the lattice mismatch and additionally by the thermal stress by the epoxy.…”