Synthesis of Fe _1+y Te Nanocrystals with Modulated Dimensionality and Properties

Abstract Dimensionality and morphology critically tailor material properties by controlling electron behavior through modifications to crystal symmetry and potential fields. However, precise dimensionality control in low‐dimensional materials remains challenging. The controlled synthesis of 2D and 1D Fe 1+y Te nanocrystals (y < 0.12) with distinct electromagnetic transport properties via chemical vapor deposition (CVD) is demonstrated. By reducing the distance between the Fe and Te sources, the morphology of Fe 1+y Te nanocrystals evolves from 2D quasi‐square and ribbon‐shaped structures to 1D nanoribbons. Spherical aberration‐corrected scanning transmission electron microscopy (STEM) analysis reveals that this dimensional transition is likely driven by intermediate phases with anisotropic formation energy. Electromagnetic transport measurements indicate that both 2D and 1D Fe 1+y Te nanocrystals undergo a structural phase transition from tetragonal to monoclinic symmetry, accompanied by a magnetic phase transition from paramagnetic to bicollinear antiferromagnetic states upon cooling. unlike the metallic behavior of 2D Fe 1+y Te, the 1D nanoribbons exhibit field‐induced semiconducting characteristics. Moreover, a charge density wave (CDW) state emerges near 22 K exclusively in the 1D nanoribbons. These findings establishes a versatile platform for dimension‐controlled fabrication of low‐dimensional materials and exploration of their emergent physical phenomena.