Analyzing the electronic and optical properties of bulk, unstrained, and strained monolayers of SrS2 by DFT

Uğur Ş., Güler E., Güler M., Özdemir A., Uğur G.

PHYSICA E: LOW-DIMENSIONAL SYSTEMS AND NANOSTRUCTURES, cilt.143, ss.115403, 2022 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 143
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1016/j.physe.2022.115403
  • Dergi Adı: PHYSICA E: LOW-DIMENSIONAL SYSTEMS AND NANOSTRUCTURES
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Applied Science & Technology Source, Compendex, Computer & Applied Sciences, INSPEC
  • Sayfa Sayıları: ss.115403
  • Anahtar Kelimeler: SrS2, Monolayer, DFT, Electronic, Optical, Strain, GENERALIZED GRADIENT APPROXIMATION, 1ST-PRINCIPLES
  • Gazi Üniversitesi Adresli: Evet

Özet

Density functional theory (DFT) calculations were conducted for the electronic and optical properties of the bulk, unstrained and strained monolayers of SrS2. Electronic band structures of the bulk SrS(2 )indicated an indirect bandgap with 1.32 eV, whereas the SrS(2 )monolayer displayed a higher indirect bandgap with 1.95 eV. Biaxial tensile strains of different magnitudes cause complex effects by increasing or decreasing the electronic band gaps of the SrS(2 )monolayer. In contrast, the various biaxial compressive strains always diminish the bandgap energy of the SrS(2 )monolayer. Furthermore, both bulk and monolayer SrS(2 )have individual low-dielectric constants suggesting their possible use in microelectronics. In addition, owing to their high refractive indices and optical conductivities in the infrared (IR) region, unstrained bulk and monolayer SrS(2 )can be effective materials for both IR and solar cell applications. Also, the observed ultraviolet (UV) absorption peaks of unstrained bulk and monolayer SrS(2 )indicate their suitability as UV absorbers. Strain-dependent optical properties of the monolayer SrS(2 )were also evaluated. Under biaxial tensile strains between 5% and 25%, monolayer SrS(2 )demonstrates optical isotropy in which its optical properties remain almost unchanged. However, biaxial compressive strains larger than 10% caused slight variations in the optical properties of the SrS(2 )monolayer. Obtained phonon dispersions curves for unstrained bulk and monolayer SrS(2 )prove the dynamical stability of these compounds. Further, SrS(2 )monolayers SrS(2 )monolayers under biaxial compressive strains up to 5% and under biaxial tensile strains up to 15% remain dynamically stable.