Nature University of Pennsylvania: Electrically driven long-range solid-state amorphization in ferroic In2Se3

The microscopic mechanisms behind the formation of amorphous and other disordered phases from ordered ones in materials have long been a subject of scientific inquiry. Amorphization typically occurs through rapid cooling of a liquid melt, bypassing the thermodynamically favored crystallization process. Electrically induced amorphization is relatively rare, with only a few material systems demonstrating this behavior through pulsed electric currents, most of which rely on melt-quenching. However, if the melting step can be avoided and solid-state amorphization achieved through electrical means, it could open up new possibilities for low-power device applications.

In this study, the authors present an energy-efficient, unconventional approach to long-range solid-state amorphization in a new ferroic β'' phase of InSe nanowires. Unlike traditional pulsed electrical methods, they apply a DC bias to induce the amorphization. The process involves a complex interplay of several factors: an electric field applied perpendicular to the polarization, a current flowing parallel to the van der Waals layers, and piezoelectric stresses. These factors lead to the formation of interlayer slip defects and in-plane polarization rotation, resulting in coupled disorder. When a critical level of electrically induced disorder is reached, the material’s structure becomes frustrated and collapses locally into an amorphous phase—a process that is also mirrored on larger microscopic scales through acoustic shocks.

This work uncovers a previously unrecognized multimodal coupling mechanism between ferroic order, applied electric fields, electrical currents, and internally generated stresses. The findings could pave the way for the design of novel materials and devices for low-power electronic and photonic applications.

Figure 1 | TEM characterization of synthesized β''-In₂Se₃ nanowires 

Paper link:

Modi, G., Parate, SK, Kwon, C. et al. Electrically driven long-range solid-state amorphization in ferroic In₂Se₃. Nature , 2024. https://doi.org/10.1038/s41586-024-08156-8