Structural, electronic, and optical properties of topological semimetal ZrSn3: A DFT study for optoelectronic and quantum device applications

Cubic α-BiF3-type topological semimetal zirconium tin (ZrSn3) is a promising candidate for next-generation quantum and optoelectronic applications due to its unique electronic topology and strong light-matter interactions. In this study, we present a comprehensive first-principles investigation of the structural, mechanical, electronic, and optical properties of ZrSn3 using density functional theory (DFT). The optimized lattice parameter a = 5.23 Å and elastic constants satisfy the Born-Huang criteria, confirming mechanical stability. Mechanical analysis reveals a semi-brittle nature Pugh's ratio G/B = 0.64, moderate hardness (∼7.7 GPa), and good machinability B/C44 = 1.48, indicating resilience for device fabrication and structural integrity under stress.Electronic band structure analysis reveals Dirac-like crossings near the Fermi level, a compensated Fermi surface with both electron- and hole-like pockets, and strong hybridization between Zr-4d and Sn-5p orbitals. Spin-orbit coupling (SOC) calculations confirm the robustness of these features, introducing minor band splitting without gap opening, thereby preserving the topological character.The optical response is equally notable: ZrSn3 exhibits high infrared reflectivity (>50 %), a large static refractive index, and broad absorption extending into the ultraviolet region. Most importantly, the energy-loss function identifies a dominant bulk plasmon resonance at ∼8.7 eV, consistent with collective electron oscillations. A secondary feature near 15.2 eV is interpreted as a weaker satellite peak or higher-lying interband transition, refining previous interpretations of the material's dielectric behavior.These multifunctional properties collectively highlight ZrSn3's potential for quantum electronics, infrared optoelectronics, UV photodetectors, plasmonic devices, and extreme ultraviolet (EUV) optical components. Overall, this study confirms the intrinsic stability, topological robustness, and tunable optical characteristics of ZrSn3, positioning it as a versatile platform for future quantum and optoelectronic technologies.