Engineering Natural Layered Framework for Low and Anisotropic Thermal Conductivity

Abstract

Abstract The development of nano–manufacture technology in the twenty‐first century has paved the way for artificial nanostructure constructions like man–made superlattices, providing historical breakthroughs in thermal physics and thermoelectrics by the modulation of phonons. Still, high–performance thermal insulators haven't come into operation due to the arduousness, costing and unscalability of artificiality. Herein, intentional engineering on a so–called ‘natural superlattice’ with alternating PbSe– and Bi2Se3–layer crystal structure is brought forth to recreate the mechanism of artificial superlattices and boost phonon localization. The thermal conductivity notably shows a direction–specific reduction, leading to minimum approaching and enhanced anisotropy. The modification of the natural framework and its effects have been supported by various transport and structure studies. This work sets a generalizable example for natural layered material engineering that bridges between the inflexible, changeless but self–assembled natural layered compounds, and the highly efficient, delicately tailored but unscalable artificial superlattice complexes. The methodology promises new horizons for practicable thermal management.

Keywords

• homologous series
• low thermal conductivity
• natural superlattices
• phonon localization
• transport anisotropy