Agradecimentos: The Article Processing Charge for the publication of this research was funded by the Coordination for the Improvement of Higher Education Personnel - CAPES (ROR identifier: 00x0ma614). The authors are grateful for the computational resources provided by Centro Nacional de Processamento de Alto Desempenho in São Paulo-CENAPAD-SP (proj 897, 909, and 950) and the Lobo Carneiro HPC (NACAD) at the Federal University of Rio de Janeiro (UFRJ) (proj 133 and 135). A.C.D. also thanks the financial support from National Council for Scientific and Technological Development (CNPq, grant number 408144/2022-0 and 305174/2023-1), Federal District Research Support Foundation (FAPDF, grants number 00193-00001817/2023-43 and 00193-00002073/2023-84), and PDPG-FAPDF-CAPES Centro-Oeste (grant 00193-00000867/2024-94). R.M.T. and D.S.G. acknowledge support from CNPq and the Center for Computational Engineering and Sciences at Unicamp, FAPESP/CEPID Grant (2013/08293-7). E.A.M. thanks the financial support of the Brazilian National Council for Scientific and Technological Development CNPq, grant number 315324/2023-6 Ver menos

Abstract: We have investigated the Raman spectrum and excitonic effects of the novel 2D Ta2Ni3Te5 structure. The monolayer is an indirect band gap semiconductor with an electronic band gap value of 0.09 and 0.38 eV, determined using GGA-PBE and HSE06 exchange-correlation functionals, respectively. Since this structure is energetically, dynamically, and mechanically stable, it could be synthesized as a free-standing material. We identify 10 Raman- and 10 infrared-active modes for various laser energies, including those commonly used in Raman spectroscopy experiments. It was also observed that the contribution of Ni atoms is minimal in most Raman vibrational modes. In contrast, most infrared vibrational modes do not involve the vibration of the Ta atoms. As far as the optical properties are concerned, this monolayer shows a robust linear anisotropy, an exciton binding energy of 287 meV, and a high reflectivity in the ultraviolet region, which is more intense for linear light polarization along the x direction Ver menos