Ferroelectricity and nanotube-induced synthesis of one-dimensional group-Ⅳ monochalcogenide nanowires

MX nanowires are a family of intrinsic 1D ferroelectrics and can be synthesized more easily in (8,8) BN-NT than in traditional CNT. [Display omitted] •MX nanowires show a family of 1D structure without dangling bonds.•MX nanowires are intrinsic ferroelectrics with special polarization intensity.•MX nanowires are easier to be synthesized in (8,8) BN-NTs than in traditional CNTs. Rapid development in micro/nano-electromechanical systems requires diverse intelligent components such as sensors, transducers and actuators with micro/nano-scale dimensions. Low dimensional ferroelectrics are expected to play a dominant role in these fields. However, with their intrinsic size decreasing to one-dimension, the ferroelectric polarization will weaken or even disappear, which seriously hinders the miniaturization trend of ferroelectric devices. Therefore, it is significant to design and synthesize one-dimensional ferroelectrics. In this work, we confirmed a series of group-Ⅳ monochalcogenide (MX, M = Ge, Sn; X = S, Se) nanowires with special ferroelectricity and investigated their synthesis induced in nanotubes using the first-principles method. Their ferroelectric characteristics including spontaneous polarization Ps and transition barrier EG, together with their stabilities, electronic structures and transformation mode were systematically investigated. The results show that they are intrinsic 1D ferroelectrics with Ps of 6.16 × 10-10 C/m, 5.88 × 10-10 C/m, 4.39 × 10-10 C/m and 3.27 × 10-10 C/m for GeS, GeSe, SnS and SnSe nanowires and can exist stably without dangling bonds. Moreover, their nanotube-induced synthesis results indicate that MX nanowires can be synthesized more easily in (8,8) boron nitride nanotubes than in traditional carbon nanotubes. These results are of great significance for experimental exploration and synthesis of 1D ferroelectrics.