In this talk I will present the problem of calculating the circular
photogalvanic effect in topological semimetals, a property for
which we would like to study the effects of symmetry breaking of. One
of the approaches explored in this ongoing project, different than in
previous studies, is to evaluate the resulting implicit surface
integrals directly. Previous studies used an artificial broadening of
the implicit surface, which converts this problem to a 3D integration.
It is solved by sampling a grid, which introduces rather high errors
of up to 2% as the grid density is pushed to numerical limits. We
will discuss different possible solutions to this problem and the
subtleties of implementing a numerical implicit surface integration.
Suggestions on different unexplored approaches to the presented
problems are welcome.
 F. de Juan, et al. Quantized circular photogalvanic effect in Weyl
semimetals. Nature communications 8.1 (2017): 1-7.
 Z. Ni, et al. Giant topological longitudinal circular
photo-galvanic effect in the chiral multifold semimetal CoSi. Nature
communications 12.1 (2021): 1-8.