Observation of infrared absorption in HgSe and HgTe in transient megagauss fields

Applying infrared-magneto spectroscopy in transient megagauss fields, we were able not only to observe detailed inter- and intraband resonances, but also to study the carrier dynamics due to the pronounced hysteresis effects in the magneto transmission. These time-delay effects are shown only at temperatures above 100 K and are strongest at room temperature in the cyclotron-resonance transitions. The effect can be explained by a delay in the thermalization of the carrier population due to a finite spin-lattice relaxation time being in the order of the characteristic time of the field variation. Choosing HgSe and HgTe as examples we demonstrate the transient megagauss fields are a useful tool for the investigation of spin related carrier dynamics in semiconductors