Abstract
Static charge screening is a fundamental topic in physics that has been extensively studied [1-30]. It refers to the way in which valence charges in condensed matter systems fluctuate and polarize to screen the external Coulomb field caused by the presence of impurities. This screening is mediated by long-range interactions between electrons and is responsible for the basic phenomena of electromagnetic theories [29, 30]. The screening ability of a material can be characterized by its dielectric function, which is defined as the ratio of the external field to the total Coulomb field, including the perturbed and induced parts [29, 30]. In classical electrodynamics, this quantity is macroscopic and is called the dielectric constant, which provides a macroscopic averaged response over all frequencies. This perspective is appropriate for a comprehensive understanding of the polarization of electrons in semiconductors or insulators. However, dealing with quantum states from a microscopic viewpoint is challenging. Electric polarization in quantum systems involves transitions of different electronic states and is closely related to the momentum and frequency of the external electric field. When free carriers in n-type or p-type metals are disturbed by impurities, the screening behavior varies depending on the electronic states’ momentum and frequency, which respond to external fields differently. Moreover, due to the long-range Coulomb interaction, a quantum phenomenon called Friedel oscillation appears. In this chapter, we present a theoretical framework that accurately calculates the dielectric function in metallic, narrow-gap, middle-gap and semi-metallic systems. We thoroughly illustrate the charge screening in the static limit of ω, → 0. Using the Fourier transform, we obtain the total Coulomb potential and induced charge density in r-space, demonstrating the effective screening length and the long-range behavior of Friedel oscillation….
Original language | English |
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Title of host publication | Rich Quasiparticle Properties in Layered Graphene-related Systems |
Publisher | World Scientific Publishing Co. |
Pages | 131-161 |
Number of pages | 31 |
ISBN (Electronic) | 9789811277795 |
ISBN (Print) | 9789811277788 |
DOIs | |
Publication status | Published - 2023 Jan 1 |
All Science Journal Classification (ASJC) codes
- General Biochemistry,Genetics and Molecular Biology
- General Engineering
- General Physics and Astronomy