Linear optical response of monolayer Sb 2 Te 3 under uniaxial strain assessed by time-dependent density functional theory

Abstract Strain engineering enables control over the optical properties of 2D materials, but systematic theoretical studies are computationally demanding. By using time-dependent density functional theory (TDDFT) with optimized hybrid functionals (B3LYP and Gau-PBE) and a long-range corrected kernel (LRC), we study strain-tunable optical properties in monolayer Sb 2 Te 3 . Uniaxial tensile strain along the x -direction induces optical anisotropy between in-plane components and modified near-infrared absorption. Both functionals yield consistent results for 0%–5% strain, validating our predictions. The TDDFT-LRC approach captures the essential physics, as validated through this comparison with more robust reference calculations, while enabling computationally tractable systematic studies for several strain configurations. Strain-induced anisotropy ( ε x x / ε y y ratios of 1.4–3 eV) suggests applications in polarization-sensitive photodetectors and strain sensors. This work presents a computational framework for strain-engineered optical properties in Sb 2 Te 3 and related chalcogenides, helping in the development of next-generation optoelectronic devices where mechanical deformation modulates optical response.