Time-resolved measurement of the anomalous velocity
The movement of charge carriers perpendicular to an electric driving field – even without a magnetic field – constitutes one of the most intriguing properties of carriers in solids. This anomalous velocity is at the origin of fascinating physical phenomena – with the spin Hall effect and the anomalous Hall effect being two prominent examples – and might be important for future spintronic applications or even new quantum computers. At PTB, researchers have now succeeded in detecting the anomalous velocity in a semiconductor made of GaAs with a sub-picosecond time resolution. On the one hand, this work gives new insight into the microscopic origins of the anomalous velocity. On the other hand, it opens a new area of research for studying important physical effects on ultrafast time scales.