Figure 3: Hanle measurements under optical pumping conditions.
From: Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field
(a) Circular polarization degree of the PL emission as a function of the applied transverse magnetic field. Measurement (black circles) at low laser power (13 nW). Red line: Lorentzian fit. (b) Overhauser shift≃0—that is, there is no measurable DNP. (c) Same measurement as a but using higher laser excitation power (1.2 μW). (d) Strong Overhauser shift under high excitation power. (e) Calculated Hanle depolarization curve using equation 8—see Methods; (f) calculated longitudinal Overhauser field (black line) using equation 7 and transverse nuclear field (blue line). The compensation points where Bn,Y+BY=0 are marked by green circles. Red line: −BY. (g) Spin temperature within ellipsoids of equal electron probability density in the dot. (h) Effective and applied magnetic fields acting on electron and nuclear spin systems for one iso-Knight shell—see Methods.
