FWI Institutskolloquium: Time-resolved transport of electron spins in nanostructures

Date

Jan 27, 2011

Time

10:30 AM - 12:00 PM

Speaker

Dr. Bernd Beschoten, RWTH Aachen, Physikalisches Institut

Language

de

Main Topic

Physik

Other Topics

Physik

Host

Susann Gebel

Description

The precise phase control of spins in semiconductor spintronic devices requires electrical means for generating spin packets with a well-defined initial phase. So far, ultrafast laser pulses have successfully been used to trigger the ensemble phase of optically generated spin packets. However, electrical methods for ensemble phase triggering remain challenging. Here, we use fast current pulses to electrically inject phase triggered spin packets across an Fe/GaAs Schottky barrier into n-GaAs. We demonstrate phase coherence by the observation of multiple Larmor precession cycles for current pulse widths down to 500 ps at 20 K. We show that the current pulses are broadened by the charging and discharging time of the Schottky barrier. At high frequencies, the observable spin coherence is limited only by the finite band width of the current pulses, which is on the order of 2 GHz. These results therefore demonstrate that all-electrical injection and phase control of spin packets at microwave frequencies is possible in ferromagnet/semiconductor heterostructures.

Last modified: May 27, 2011, 4:37:41 PM