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A response by X.Q. Liu and colleagues to a letter to the editor about their article "New Structural Picture of the Ge2Sb2Te5 Phase-Change Alloy," in a 2011 issue of the journal is presented.

While being extensively studied as an important physical process to alter exciton population in nanostructures at the fs time scale, carrier multiplication has not been considered seriously as a major mechanism for phase transition. Real-time time-dependent density functional theory study of Ge2Sb2Te5 reveals that carrier multiplication can induce an ultrafast phase transition in the solid state despite that the lattice remains cold. The results also unify the experimental findings in other semiconductors for which the explanation remains to be the 30-year old phenomenological plasma annealing model. [ABSTRACT FROM AUTHOR]

The very first in-ring reaction experiment at the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR), namely proton elastic scattering on stable 58Ni nuclei, is presented. The circulating 58Ni19+ ions with an energy of 95 MeV/u were interacting repeatedly with an internal hydrogen gas target in the experimental storage ring (CSRe). Low-energy proton recoils from the elastic collisions were measured with an ultra-high vacuum compatible silicon-strip detector. Deduced differential cross sections were normalized by measuring k-shell x rays from 58Ni19+ projectiles due to the 58Ni19+-H2 ionization collisions. Compared to the experimental cross sections, a good agreement has been achieved with the theoretical predictions in the measured region, which were obtained by using the global phenomenological optical model potentials. Our results enable new research opportunities for optical model potential studies on exotic nuclides by using the in-ring reaction setup at the HIRFL-CSR facility. [ABSTRACT FROM AUTHOR]