Giant conductivity of mobile non-oxide domain walls

Atomically sharp domain walls in ferroelectrics are considered as an ideal platform to realize easy-to-reconfigure nanoelectronic building blocks, created, manipulated and erased by external fields. However, conductive domain walls have been exclusively observed in oxides, where domain wall mobility and conductivity is largely influenced by stoichiometry and defects. Here, we report on giant conductivity of domain walls in the non-oxide ferroelectric GaV4S8. We observe conductive domain walls forming in zig-zagging structures, that are composed of head-to-head and tail-to-tail domain wall segments alternating on the nanoscale. Remarkably, both types of segments possess high conductivity, unimaginable in oxide ferroelectrics. These effectively 2D domain walls, dominating the 3D conductance, can be mobilized by magnetic fields, triggering abrupt conductance changes as large as eight orders of magnitude. These unique properties demonstrate that non-oxide ferroelectrics can be the source of novel phenomena beyond the realm of oxide electronics.

Elucidation of the Mechanism for Maintaining Ultrafast Domain Wall Mobility Over a Wide Temperature Range

To realize a data rate of 20 Gbps in the communication standard 5G with a racetrack memory, it is crucial to stably recognize a domain-wall (DW) velocity (vDW) of 1200 m/s when the minimum bit length is 60 nm. However, general vDW is as slow as about 100 m/s. Recent reports indeed showed that the fast DW motion occurs using an in-plane external magnetic field however, this mechanism is unsuitable because the rear-edge vDW decelerated, which contrary to the front-edge of DW velocity. Therefore, we designed magnetic wires by bringing the g values of rare-earth and transition-metals close to each other and suppressing the Joule heat generation distribution due to short pulse current, we successfully demonstrated the vDW of 1200 m/s in a wide temperature range without using an external magnetic field. Moreover, the current density (J) is low, and the DW mobility (vDW/J) is significantly improved 10-times over a wide temperature range compared to other reports.