Maldistribution of Chemical Bond Strength Inducing Exceptional Anisotropy of Thermal Conductivity in Non‐Layered Materials

Abstract

Currently, the efforts to find materials with high k anisotropy ratios mainly focus on layered materials, however, the limited quantity and lower workability comparing to non-layered ones boost the exploration of non-layered materials with high k anisotropy ratios. Here, taking PbSnS 3 , a typical non-layered orthorhombic compound, as an example, we propose that maldistribution of chemical bond strength can lead to large anisotropy of k in non-layered materials. Our result reveals that the maldistribution of PbÀ S bonds lead to obvious collective vibrations of dioctahedron chain units, resulting in an anisotropy ratio up to 7.1 at 200 K and 5.5 at 300 K, respectively, which is one of the highest ever reported in non-layered materials and even surpasses many classical layered materials such as Bi 2 Te 3 and SnSe. Our findings can not only broaden the horizon for exploring high anisotropic k materials but also provide new opportunities for the application of thermal management.

Interlayer Phonon Coupling from Heavy and Light Sublayers in a Natural Van der Waals Superlattice

“…Finally, the tube was cooled to room temperature. We note that the attempt to obtain the superlattice without Fe and Sb is unsuccessful, leading to the product of PbSnS 3 , which is an orthorhombic ternary sulfide …”