Non-Arrhenius threshold switching by field-driven dipolar ordering.

Abstract

The long-standing challenge in resolving the atomic-scale threshold switching mechanism in amorphous chalcogenides, fundamental constraint on further development of promising memory technologies, stems from their intrinsic structural disorder. Here, we overcome this pivotal challenge by capturing electric-field-driven dipolar ordering in amorphous GeSe through combined atomic-resolution angstrom-beam electron diffraction and field-coupled ab initio molecular dynamics. Electric fields induce anti-parallel displacements of Ge ( + 0.23 Å) and Se ( - 0.21 Å) atoms within picoseconds, aligning dipoles into one-dimension chains. These polarity-locked chains, evidenced by two distinct diffraction spots (1.95 Å spacing), guide conductive filament growth perpendicular to chain alignment. This mechanism enables direct harnessing of dipole-originated threshold voltage asymmetry in selector-only memory, achieving dual functionality through single-material engineering. This field-induced non-Arrhenius process squashes thermal activation barriers, enabling dipolar-order-driven switching within the picosecond regime thus breaking the thermal speed limit for resistive switching. Our findings establish a pathway to atomic-scale dipole control for ultrafast storage-class memory.