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

Abstract

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’ B1g/B3g 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. © 2025 The Authors