What is the relationship between the conductivity and thermal conductivity of materials

There is a certain relationship between the conductivity and thermal conductivity of materials. Conductivity is the ability of a material to conduct current, while thermal conductivity is the ability of a material to conduct heat. Both of these properties are related to the electron and heat conduction inside the material.

Generally speaking, both conductivity and thermal conductivity are related to the density of free electrons in the material. In metals, the valence electrons in atoms form a highly mobile electron gas. These free electrons can freely transfer current and heat, resulting in high conductivity and thermal conductivity of the metal.

Compared to metals, insulators and semiconductors have poor conductivity and thermal conductivity. In insulators, there can be a small number of free electrons, but their density is very low, resulting in poor current and heat conduction. Semiconductors have conductivity and thermal conductivity between insulators and metals. In semiconductors, the conductivity of electrons can be significantly altered by changes in applied electric field or temperature.

In addition, the lattice structure and defects of materials can also affect their conductivity and thermal conductivity. The integrity and periodicity of the lattice structure play an important role in the transmission of electrons and heat. And defect sites such as defects, impurities, and interfaces can scatter electrons and hot electrons, thereby reducing conductivity and thermal conductivity.