Observation Of Phase Transitions Of Ba0.6sr0.4tio3-Silicon Hybrid Metamaterial By Thz Spectra

The ferroelectric thin film such as BaSrTiO3 (BST), exhibiting great tunable characteristics, is a hot spot in photonic devices for both microwave and terahertz frequencies. This report presents a cryogenic temperature measurement of a Ba0.6Sr0.4TiO3-silicon hybrid metamaterial by terahertz time-domain spectroscopy. Three phase transitions of the BST thin film are observed in the THz spectra, including cubic-tetragonal (C-T), tetragonal-orthorhombic (T-O), and orthorhombic-rhombohedral (O-R). We also investigated the modulation of its dielectric properties in different temperature conditions, which delivers a transmittance contrast up to similar to 45.8%. These findings provide a reference to the ferroelectric basic research and can be generalized for use in ferroelectric thin-film-based temperature sensors.