Ab initio дослідження оптичних характеристик антиферомагнетика FePS3

Introduction. Layered thiophosphates FePS3 is the van-der-Waals crystal with interesting physical and chemical properties. In particular, its layered structure gives a clear pathway to obtain the 2D material by exfoliation method. Exhibiting high structural anisotropy, the mentioned material can be intercalated by alkali metal ions without any significant distortion of lattice parameters, making it promising candidate for the creation of low-cost cathodes for high-energy-density batteries. An electronic band-structure model for FePS3 crystal is needed for both academic and technological reason.Purpose. The main aim of our paper is to carry out a complete DFT-based search to investigate of the electronic and optical properties for the antiferromagnetic compound FePS3.Methods. Quantum chemical calculations in this work were performed in the framework of density functional theory (DFT) within local approximation for exchange-correlation interaction (LDA) and dispersion correction (DFT-D) methodology. Optical properties obtained from calculated e1 and e2 energy dependencies.Results. In the results of our work, the electronic and optical properties of FePS3 crystal were investigated. In addition, the energy band spectra and partial density of state for the antiferromagnetic phase of FePS3 crystal were calculated. Also, the real and imaginary part of dielectric insensitivity, refractive index and absorption index from first principle calculations were obtained.Conclusion. For the first time we carried out the investigations of the optical characteristics for the FePS3layered antiferromagnetic on the basis of the electronic band spectrum calculation. The detail analysis of the optical spectra and the evaluations of the refractive index and dielectric constants shows the essential anisotropy in the different energy ranges. Our results for electronic and optical properties are compared with the experimental and other theoretical results. В данной работе проведено исследование электронных и оптических свойств слоистого кристалла FePS3. Впервые рассчитаны энергетический зонный спектр и парциальные плотности состояний с использованием ab initio подходов. Основываясь на расчётах зонной структуры, получены энергетические зависимости оптических характеристик, а именно, действительная и мнимая части диэлектрической проницаемости, показатель преломления и показатель поглощения кристалла FePS3.У даній роботі проведено дослідження електронних та оптичних властивостей шаруватого кристалу FePS3. Вперше розраховано енергетичний зонний спектр та парціальні густини станів з використанням ab initio підходу. Базуючись на розрахунках зонної структури, одержано енергетичні залежності для оптичних характеристик, а саме дійсна і уявна частина діелектричної проникливості та показник заломлення і показник поглинання кристала FePS3