
Full figure (27 kB)Fig. 1. (Color) (a) Schematic of the experimental setup and stress geometry. The laser is directed along the growth axis (z axis). A threaded rod (1) pushes the wedge (2) past the chip breaker (3), forcing it against the back of the sample. Strain is produced (4) in the plane of the sample, compressive in the rear and tensile in the active layer (black region). (b) Kerr rotation as a function of delay time for the strained (solid line) and unstrained (open circle) areas of the sample (T=5 K). The Kerr rotation
K is proportional to the conduction electron polarization along z.
L can be obtained from the period of the oscillations in the Kerr rotation, T
from the curve decay. First citation in article
Full figure (36 kB)Fig. 2. (Color) (a) Top down, spatial maps of donor-bound exciton group PL, C
exciton group PL, effective g factor, and T
over the entire sample. Symbols from line cuts in (c) pictured on images. (b) PL from strained (square) and unstrained (circle) areas of the sample. Overlaid are Lorentzian fits used to extract peak shifts. (c) Line cuts along X of C
group PL energy (solid square), effective g factor (open square), and T
(open circle) from spatially resolved maps in Fig. 2(a). For the PL, the maximum shift on the center is ~10 meV. The TRKR and PL measurements are performed at T=5 K. First citation in article
Full figure (36 kB)Fig. 3. (Color) (a) NMR transitions for maximum (solid line) and minimum (open circle) strain. Arrows highlight resonant nuclear depolarization at (from left to right)
B=29, 4, +4, and +29 mT. (b) X dependence of the NQR field along the sample. Pictured in the center is a schematic of the line cut orientation. Transitions are plotted in nuclear frequency shift (left) and magnetic field (right). (c) Dynamically polarized nuclear field vs laboratory time for varying strains. The square symbol is for the lowest strain; triangle is for the highest (T=10 K). (d) Y dependence of NQR field. Unless noted, all measurements are performed at T=5 K. First citation in article