Giant switchable metallic-like conduction in 180° domain walls in tetragonal Pb(Zr,Ti)O3

Abstract

Conductive domain walls in ferroelectrics offer a promising concept of nanoelectronic circuits with 2D domain-wall channels playing roles of memristors or synoptic interconnections. However, domain wall conduction remains difficult to control and pA-range currents typically measured on individual walls are too low for single-channel devices. Charged domain walls show higher conductivity, but are generally unstable and difficult to create. Here, we show highly conductive and stable channels on ubiquitous 180°-domain walls in the archetypical ferroelectric, tetragonal Pb(Zr,Ti)O3. These electrically erasable/rewritable channels show tens of nanoamperes (200-400nA/μm) at voltages ≤2V and metallic-like non thermally-activated transport properties down to 4K, as confirmed by nanoscopic mapping. The domain structure analysis and phase-field simulations reveal complex switching dynamics, in which the extraordinary conductivity in strained Pb(Zr,Ti)O3 films is explained by an interplay between ferroelastic 90°-domains and 180°-domains. This work demonstrates the potential of accessible and stable arrangements of nominally uncharged domain walls for nanoelectronics.