Preferred synthesis of armchair transition metal dichalcogenide nanotubes

Nanotubes represent an important class of crystalline materials, but controlling their structures, particularly chiralities, remains a fundamental challenge. In this work, we report a strategy for synthesizing transition metal dichalcogenide nanotubes with preferred armchair chirality. Tin disulfide, molybdenum disulfide, and tungsten disulfide nanotubes were formed with high yield and structural purity inside boron nitride nanotube channels. Atomic-resolution imaging, electron diffraction, and circular dichroism revealed an armchair preference up to 83%. Density functional theory ruled out structural stability as the origin of this preference but confirmed that zigzag nanoribbons are energetically more stable. Machine learning potential molecular dynamics simulated that zigzag nanoribbons roll up to form armchair nanotubes, a process that was subsequently observed by in situ transmission electron microscope. This work may inspire the achievement of on-demand synthesis of various nanotubes with specific chiralities.