Unveiling electric-field-driven deformation dynamics in metal nanostructures.

Electric-field-induced effects severely impact the long-term stability and reliability of nanoelectronic devices with nanogaps, such as field emission nanodiodes, field-effect nanotransistors and ultrafast switches. However, the damage mechanisms behind nanostructured electrode under high electric fields remain unclear. Here, we investigate deformation behaviors of tungsten nanotips, a typical nanostructured electrode, under an external electric field ( ~ 10 V/nm) using an in situ transmission electron microscopy (TEM), presenting the direct observation of both surface morphological evolution and dislocation dynamics. We find that electron wind effects and nanoscale effects dramatically reduce the atom evaporation threshold to 10-13 V/nm, which is approximately one-fourth to one-fifth of the previously reported values of 40-60 V/nm. Furthermore, we identify a field-induced deformation mechanism where strong electric fields and emission currents generate substantial, size-dependent structural changes closely governed by crystallographic orientation (Wulff shape) without external heating, occurring primarily through field-assisted evaporation rather than conventionally assumed field-induced surface atom diffusion. These findings enhance the understanding of electric-field-induced damage and are crucial for nanoelectronic devices optimization, reliability, and lifetime evaluation.