A multifunctional 2D goldene monolayer with strain-sensitive optoelectronic and thermoelectric properties

Goldene, a two-dimensional (2D) monolayer (ML) of gold (Au) atoms, has recently gained attention due to its distinctive structural and electronic features. Driven by the possibility of modifying material properties through strain engineering, this work explores the structural, electrical, optical, and thermoelectric properties of goldene ML using density functional theory (DFT). Both the pristine ML and its response under applied biaxial mechanical strain (compressive and tensile) are systematically analyzed. Our results show that goldene remains metallic under all applied biaxial strains, with no band gap opening, while strain induces notable modifications in its electronic density- of -states and transport properties. Goldene exhibits a strong low-energy reflectivity peak, reaching 0.55 under - 10% compressive strain and 0.37 under + 10% tensile strain, highlighting the tunability of its optical response via strain engineering. The static refractive index increases from 0.74 (unstrained) to 0.77 under - 10% compressive strain, while tensile strain reduces it to 0.71, indicating that strain can effectively tune its optical confinement and dielectric response. Power factor (PF) is strongly enhanced under compressive strain, reaching a maximum of 9.10 × 10¹¹ W/mK²s at -2% strain and 300 K, nearly an order of magnitude higher than the pristine value of 1.3 × 10¹¹ W/mK²s, highlighting the effectiveness of strain engineering for thermoelectric optimization. *corresponding author: akmishra@ddn.upes.ac.in (email).