Thank you Devika for the reply but the link "Ansys Insight: How to add new material into the optical material library" describes only how to add a material in the optical library. I am searching for a way to add a new material into the Thermal materials database, not the optical library. I know how to add material in the optical library but for the thermal database, there is not any explanation. Also, the link "Material Database in Finite Element IDE (CHARGE, HEAT, DGTD, FEEM, MQW) - Ansys Optics" does not explain how to add a new material into the thermal material database. The link shows that someone can create, modify and delete. The "create" option just imports to the simulation an already existing material from the thermal database, it doesn't create a new material.                                                                                                                                         

I thought as a solution to add a new material but I am not sure if it is correct. Please see the following steps:

  1. I selected an existing material,
  2. I duplicated it and I renamed the copy duplicate material to a new name
  3. I modified the thermal properties so as to be similar to the material that I want 

So, I will modify the density, the specific heat, the thermal conductivity and the electrical conductivity. Is my thought correct?