Resonant Fano interaction in B1g/B3g Raman mode under off-resonant excitation in V2O5 μ-crystals: Thermal phonon as facilitator

Understanding electron-phonon (Fano) interactions, by employing techniques like Raman spectroscopy, in materials proves important in designing them for appropriate optoelectronic applications and extracting optimized performance. Orthorhombic vanadium pentoxide (V₂O₅) micro crystallites' B_1g/B_3g mode around 702 cm^-1 has been investigated to establish that this mode shows a resonant Fano interaction. Suitably designed wavelength and temperature-dependent Raman measurements collect sufficient evidence to establish that Fano-Raman line-shape can be observed under off-resonant excitation also if the system's temperature is elevated to generate sufficient thermal phonons in V₂O₅. Such resonant Fano interactions can be made possible due to the involvement of thermal phonons as a facilitator which acts as a bridge between the discrete phonons and electronic continuum to initiate the quantum interference. A non-linear dependence of the Fano coupling parameter on temperature was observed. A quantum mechanical framework has been suggested to elucidate the temperature-dependent resonant characteristics of Fano interaction under off-resonant excitation in V₂O₅.