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Raman spectroscopy is a widely used, powerful, and nondestructive tool for studying the vibrational properties of bulk and low-dimensional materials. Raman spectra can be simulated using first-principles methods, but due to the high computational cost calculations are usually limited only to fairly small unit cells, which makes it difficult to carry out simulations for alloys and defects. We recently developed an efficient method for simulating Raman spectra at nearly first-principles accuracy of (certain) systems which commonly require excessively large supercells. In my talk, I will introduce the method and demonstrate its applicability in the case of 2D materials when the parent material is modified through alloying, introduction of defects, or stacking of layers, although the approach is not limited to 2D materials and should be applicable to any crystalline solid with defects and impurities. As a result, we can not only provide simulated spectra that can be directly compared to the experimental one, but also gain atomistic insight on the modifications of the vibrational spectra that are responsible for the observed changes.

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Hannu-Pekka Komsa, Aalto University, Finland
Seminar Room of the Institute of Physics II
Contact: T. Michely