https://doi.org/10.1140/epjp/s13360-025-06201-7
Regular Article
Modified Lorentz oscillator on modeling the dielectric function of Si and Ge
1
National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology (SIMIT), Research Center for New Energy Technology (RCNET), Chinese Academy of Sciences (CAS), 201800, Jiading, Shanghai, People’s Republic of China
2
University of Chinese Academy of Sciences (UCAS), 100049, Shijingshan, Beijing, People’s Republic of China
a
zlp_wan@mail.sim.ac.cn
b
z.x.liu@mail.sim.ac.cn
Received:
24
January
2025
Accepted:
8
March
2025
Published online:
10
April
2025
The classical Lorentz model is widely used for modeling the dielectric function of insulators. However, it has failed to reproduce the experimental spectra of semiconductors in certain cases. The dielectric response over a wide range of photon energies can be easily understood using the equation of motion for electrons at different energies, particularly those below the optical bandgap. In this study, the Lorentz oscillator was modified to satisfy the Clausius–Mossotti relation, enabling the derivation of a modified Lorentz oscillator suitable for semiconductors. The dielectric response was then analyzed within the framework of the proposed dielectric function model for both the fundamental interband region and the region below the optical bandgap. The fitting results for crystalline silicon (Si) and germanium (Ge) showed that this model can provide satisfactory fitting results from above the reststrahlen region to the interband region. The properties of the dielectric function then can be better understood in terms of the motion of electrons in regions with different photon energies. In addition, the proposed model was used to calculate the static dielectric constants of Si and Ge, the values of which are very close to the actual value. The results indicate that the proposed model is an effective method for determining the static dielectric constant.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjp/s13360-025-06201-7.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
