Comment on the relationship between electrical and optical conductivity used in several recent papers published in the journal of materials science: materials in electronics

• Published in: Journal of materials science. Materials in electronics Vol. 33; no. 6; pp. 2889 - 2898
• Main Author: Aly, Kamal A.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2022; Springer Nature B.V
• Subjects: Absorptivity; Characterization and Evaluation of Materials; Chemistry and Materials Science; Conductivity; Electrical resistivity; Electronics; Letter to the Editor; Light speed; Materials Science; Optical and Electronic Materials; Refractivity
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-07496-9

Recently a series of papers have been published in the Journal of Materials Science: Materials in Electronics and also in other journals in which a relationship of the form σ el = 2 k n c / α , σ el = 2 λ σ op / α  and σ el = λ nc / ( 2 π ) (where λ is the free-space wavelength of light c is the speed of light in vacuum) between the electrical conductivity σ el and optical conductivity σ 1op . The  refractive index n , absorption coefficient α and the extinction coefficient k have been used and conclusions have been drawn from these relationships, including graphs of electrical and optical conductivity as a function of photon energy over a very wide range (e.g., 1–5.6 eV). In this comment, the difference between the optical ( σ op ) and electrical ( σ el ) conductivities is considered and analyzed through well-known textbook considerations; correct relations are given, and it is shown that the above expressions that have recently appeared in the literature are incorrect.