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First-principles molecular dynamics simulation reveals the effects of electronic excitation in the amorphization of Ge-Sb-Te. The excitation makes the phase change an element-selective process, lowers the critical amorphization temperature considerably, for example, to below 700 K at a 9% excitation, and reduces the atomic diffusion coefficient with respect to that of melt by at least 1 order of magnitude. Noticeably, the resulting structure has fewer wrong bonds and significantly increased phase-change reversibility. Our results point to a new direction in manipulating ultrafast phase-change processes with improved controllability.

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Phase‐change memory (PCM) materials, such as chalcogenide alloys, have the ability for fast and reversible transition between their amorphous and crystalline states. Owing to the large optical/electrical contrast of the two states, PCM materials have been developed for data storage. It has been generally accepted that thermal effects, caused by laser irradiation or electrical pulses, control the amorphization by melting the sample and subsequent quenching, while crystallization is realized by thermal annealing. An important element that has not been considered extensively, however, is the role of electronic excitation by optical or electrical pulse. Strictly speaking, until electrons and holes recombine, the system under external stimulus is in a non‐equilibrium environment, especially when the excitation intensity is high. This raises an important question: can the excitation alone induce phase transition for PCM data storage without the usual thermal melting? Here, we will review the recent experimental and theoretical indications and evidence in support of the electronic excitation‐induced phase change in PCM materials and discuss potential ramifications of the athermal phase‐change phenomenon for data storage.

The plastic deformation features of intrinsic brittle-featured SiC nanowires by high resolution electron microscopy have been investigated. Strong plastic deformation strain fields were observed in a bent SiC nanowire. The achieved localized strain reaches about 1.5%. Localized lattice bending, atomic lattice disordering, and amorphization are contribution factors to achieve the plastic deformation. The projected Si–Si bonding angle distribution on the (110) atomic plane demonstrates the disordering features of the bent SiC nanowire. Buckling is found at the compressive side of the bent SiC nanowire. Growth bending can be achieved through {111} twinning and phase transformation from 3C to 2H.