Precise measurement of correlation parameters driving optical transparency in CaVO3 thin film by steady state and time resolved terahertz spectroscopy

Abstract

Transparent conducting materials are inevitable in the fast-developing optoelectronic and photovoltaic industries. Correlated metals are emerging classes of materials that possess a charge density comparable to the metals in which the correlation effects provide transparency. So, understanding the fundamental physics of these materials is equally important to improve the performance of devices. We have investigated the low energy and non-equilibrium dynamics of the CaVO3 (CVO) thin film using terahertz time-domain and time-resolved terahertz spectroscopic measurements. Though the electrical resistivity of the CVO thin film shows a Fermi liquid-like signature, the terahertz conductivity dynamics unveil the presence of metal-insulator transition. Furthermore, the mass renormalization effects indicate the competition between electron correlations and phonon interactions in driving the ground state of this system. It is clear that the relaxation of photo-excited carriers is through electron–phonon thermalization, and comprehensive studies show the metallic nature of the system with electron correlations. Thus, the extracted optical and electrical parameters of CVO are comparable with the existing transparent conducting materials and, hence, make this system another potential candidate for transparent electronics.