Optical Properties of Highly Conductive SrMoO₃ Oxide Thin Films in the THz Band and Beyond

Strontium molybdate (SrMoO₃) thin films are grown epitaxially by pulsed laser deposition onto gadolinium scandate (GdScO₃) substrates and characterized in the terahertz (THz) and visible part of the electromagnetic spectrum. X-ray diffraction measurements prove a high crystallinity and phase-pure growth of the thin films. The high-quality SrMoO₃ thin films feature a room temperature DC conductivity of around 3 1/μΩm. SrMoO₃ is characterized in the THz frequency range by time domain spectroscopy. The resulting AC conductivity is in excellent agreement with the DC value. A Lorentz-Drude oscillator approach models the THz and visible conductivity of SrMoO₃ very well. We compare the results of the SrMoO₃ thin films to a standard, sputtered gold film, with a resulting THz conductivity of 8 1/μΩm. The comparison demonstrates that oxide thin film–based devices can play an important role in future THz technology.