Unfolding phonon spectra by smearing of vibrational eigenmodes

Gordienko, A. B.; Gordienko, Kirill; Kopytov, A. V.

doi:10.1002/pssb.201700213

Cited by 1 publication

(1 citation statement)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In alloys or defective systems, where the translational symmetry is broken, the unfolding/projection procedure still works, but leads to each SC mode having contributions from q-points throughout the PC BZ with different weights. This type of unfolding procedures have already been used in the past to analyze both the electronic and phonon band structures of alloys [44][45][46][47]. Baroni et al found that the GDOS of the primitive cell can be used to closely approximate the Raman spectra [42] in alloys.…”

Section: A Theoretical Frameworkmentioning

confidence: 99%

Efficient method for calculating Raman spectra of solids with impurities and alloys and its application to two-dimensional transition metal dichalcogenides

Hashemi

Krasheninnikov

Puska

et al. 2019

Phys. Rev. Materials

View full text Add to dashboard Cite

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. Here, we develop an efficient method for simulating Raman spectra of alloys, benchmark it against full density-functional theory calculations, and apply it to several alloys of two-dimensional transition metal dichalcogenides. In this method, the Raman tensor for the supercell mode is constructed by summing up the Raman tensors of the pristine system weighted by the projections of the supercell vibrational modes to those of the pristine system. This approach is not limited to 2D materials and should be applicable to any crystalline solids with defects and impurities. To efficiently evaluate vibrational modes of very large supercells, we adopt mass approximation, although it is limited to chemically and structurally similar atomic substitutions. To benchmark our method, we first apply it to MoxW (1−x) S2 monolayer in the H-phase, where several experimental reports are available for comparison. Second, we consider MoxW (1−x) Te2 in the T'-phase, which has been proposed to be 2D topological insulator, but where experimental results for the monolayer alloy are still missing. We show that the projection scheme also provides a powerful tool for analyzing the origin of the alloy Raman-active modes in terms of the parent system eigenmodes. Finally, we examine the trends in characteristic Raman signatures for dilute concentrations of impurities in MoS2. :1902.02143v1 [cond-mat.mtrl-sci] arXiv

show abstract