Coherence Control of Hall Charge and Spin Currents

Abstract

Using two-color optical coherence control techniques in intrinsic GaAs at 80 K with orthogonally polarized 70 fs, 1430 and 715 nm pulses, we generate a pure spin source current that yields a transverse Hall pure charge current; or alternatively, with parallel polarized pulses, we generate a pure charge source current that yields a pure spin current. By varying the relative phase or polarization of the incident pulses, one can effectively tune the type, magnitude and direction of both the source and transverse currents without application of electric or magnetic fields.

Second-Harmonic Generation Induced by Electric Currents in GaAs

“…Here N 2D is the areal carrier density. We note that although current injection by the coherent control technique has been demonstrated in many materials by steady-state electric measurement, terahertz detection, and spatially resolved pump-probe techniques, [11,19,20,[23][24][25] the current-induced SHG demonstrated here allows us to time-resolve the ultrafast dynamics of these currents.…”

“…With both pulses being linearly polarized along an arbitrarily chosenx direction, electrons are excited to the conduction band with an average velocity v 0 sin(∆φ)x, where ∆φ is the relative phase of the two transition amplitudes, and v 0 is on the order of 30 nm/ps. [11,[17][18][19][20][21] With a carrier density on the order of 10 17 − 10 18 /cm 3 ,…”

Temperature dependence of ambipolar diffusion in silicon on insulator

“…In order to achieve sufficient signal-to-noise ratio in measuring ∆T /T 0 , balanced detection and lockin detection are combined. 13,14,15 As shown in Fig. 1, a portion of the probe pulse is taken before the sample as a reference pulse, and is measured by one photodiode of a balanced detector.…”

Inverse spin Hall effect by spin injection

“…It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering, while its spatial variation is determined by the intrinsic spin-orbit coupling. [7,8,9,10].The SO coupling mechanism can also lead to a reciprocal SHE effect, the "inverse spin-Hall effect" (ISHE), which was predicted by Hirsch [2]. When a purely longitudinal spin current is applied, the electrons with opposite spins, flowing in opposing longitudinal directions, move toward the same transverse side of the sample due to SO interaction, resulting in charge accumulation.…”

“…It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering, while its spatial variation is determined by the intrinsic spin-orbit coupling. [7,8,9,10].…”