Dielectric function with band theory

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Dielectric function can be computed using band structure, but it presents challenges since band structure is a global property while dielectric function is local. Calculating the dielectric function at specific points, such as surfaces or within the bulk, is complex due to its dependence on both spatial variables. For bulk points, the dielectric function primarily depends on the distance between points, which decays rapidly at atomic or lattice scales. Fourier transformation allows for the calculation of the dielectric function using k-dependent Bloch states, with the macroscopic dielectric constant typically reported as epsilon(k=0). Further literature on this topic includes a recommended book that provides additional insights into the dielectric function.
taishizhiqiu
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As far as I am concerned, dielectric function can be computed by band structure. However, band structure is a global property of solids, while dielectric function is a local property. How a local property can be computed from a global property.

Put it another way, if I want to calculate dielectric function for a specific point(for example, on the surface or deep in the bulk), how can I do it with band structure? Or there is a concept called local band structure?
 
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The calculation of a dielectric function for non-translationally invariant systems is very complicated as it will depend on both r and r' as ##D(r)=\int dr' \epsilon(r,r') E(r')##(dependence on omega understood) and cannot be done from a bulk band structure. For a point inside the bulk, epsilon will only depend on the distance (r-r') and this dependence decays normally rapidly to zero on a distance of the order of the atomic or lattice spacing.
Fourier transforming gives ##\epsilon(k)## which can be calculated using the k-dependent Bloch states. The macroscopic dielectric constant which is usually reported is epsilon(k=0).
 
DrDu said:
The calculation of a dielectric function for non-translationally invariant systems is very complicated as it will depend on both r and r' as ##D(r)=\int dr' \epsilon(r,r') E(r')##(dependence on omega understood) and cannot be done from a bulk band structure. For a point inside the bulk, epsilon will only depend on the distance (r-r') and this dependence decays normally rapidly to zero on a distance of the order of the atomic or lattice spacing.
Fourier transforming gives ##\epsilon(k)## which can be calculated using the k-dependent Bloch states. The macroscopic dielectric constant which is usually reported is epsilon(k=0).
Can you provide me with some literature?
 
A relative asked me about the following article: Experimental observation of a time rondeau crystal https://www.nature.com/articles/s41567-025-03028-y I pointed my relative to following article: Scientists Discovered a Time Crystal That Reveals a New Way to Order Time https://www.yahoo.com/news/articles/scientists-discovered-time-crystal-reveals-180055389.html This area is outside of my regular experience. I'm interested in radiation effects in polycrystalline material, i.e., grain...

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