Unveiling Electric-Field-Driven Deformation Dynamics in Metal Nanostructures

Electric-field-induced damage severely impacts the long-term stability and reliability of nanoelectronic devices with nanogaps, such as field emission nanodiodes, field-effect nanotransistors and especially ultrafast switches recently reported in Nature that demonstrated revolutionary picosecond switching speeds and breakthrough terahertz potential. 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 first 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 V/nm, a striking five-fold reduction from the theoretical prediction of ~ 50 V/nm. Furthermore, we identify a novel 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.