Synthetic Nanosheets of Natural van der Waals Heterostructures

Creation of new van der Waals heterostructures by stacking different two dimensional (2D) crystals on top of each other in a chosen sequence is the next challenge after the discovery of graphene, mono/few layer of h ‐BN, and transition‐metal dichalcogenides. However, chemical syntheses of van der Waals heterostructures are rarer than the physical preparation techniques. Herein, we demonstrate the kinetic stabilization of 2D ultrathin heterostructure (ca. 1.13–2.35 nm thick) nanosheets of layered intergrowth SnBi 2 Te 4 , SnBi 4 Te 7 , and SnBi 6 Te 10 , which belong to the Sn m Bi 2 n Te 3 n + m homologous series, by a simple solution based synthesis. Few‐layer nanosheets exhibit ultralow lattice thermal conductivity ( κ lat ) of 0.3–0.5 W m −1  K −1 and semiconducting electron‐transport properties with high carrier mobility.