"Ultrafast terahertz-induced response of GeSbTe phase-change materials "

Michael J. Shu: Peter Zalden, Frank Chen, Ben Weems, Ioannis Chatzakis, Feng Xiong, Rakesh Jeyasingh, Matthias C. Hoffmann, Eric Pop, H.-S. Philip Wong, Matthias Wuttig and Aaron M. Lindenberg; Applied Physics Letters, 06/24/14.

Additional Authors: Peter Zalden, Frank Chen, Ben Weems, Ioannis Chatzakis, Feng Xiong, Rakesh Jeyasingh, Matthias C. Hoffmann, Eric Pop, H.-S. Philip Wong, Matthias Wuttig and Aaron M. Lindenberg

Abstract:

The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200‚ÄČkV/cm.