Room-Temperature Ferroelectricity in Group-IV Metal Chalcogenide Nanowires.

The realization of low-dimensional ferroelectrics is both fundamentally intriguing and practically appealing, to be used in nanoscale devices. Here, GeS and SnS nanowires are predicted to be one-dimensional (1D) ferroelectrics with inversion symmetry spontaneously broken by soft optical modes. Despite the low dimensionality, the estimated Curie point for GeS nanowires is above room temperature, benefiting experimental detection and suggesting realistic applications. To this end, further aspects of these 1D ferroelectrics are also examined, revealing the domain wall localization, switchable carrier mobility, and practically effective shieling by confining the nanowires inside the carbon nanotubes, all together potentially useful for nanoscale ferroelectric devices of broad interest.