IMF2017

Ferroelectric polarization can be reversed by mechanical force, thermal heating, electron/light illumination, gas pressure or electrical fields, enabling applications in spatial visualization, electrochemical sensors, and terabit non-volatile ferroelectric memories with ns-to-ps programming times, near-unlimited cycle endurance and low energy consumption. One significant challenge for these applications is the current capacitor-based technology that destructively reads out domain information through charge integration, requiring memory cells with >250 nm lateral sizes, although mechanical probe-based technology has demonstrated huge ferroelectric storage capacity of several Tb/in². Here we show a nanoscale non-destructive ferroelectric polarization readout method via electrical opening of charged-domain-wall conduction paths near the film surface layer under a horizontal read field. Our method is not only applicable for epitaxial BiFeO₃ thin films on (001) SrTiO₃ substrates with a diagonal polar axis but also successful for other nonorthogonal ferroelectrics. They have mesa-geometry three-terminal structures and functions via instantaneous domain-wall conduction upon voltage application. The operation principle of newly explored devices combines the merits of non-volatile ferroelectric memory and current-sensing resistance switching memory in ultrahigh storage density.