Tunable, Low Optical Loss Strontium Molybdate Thin Films for Plasmonic Applications

TL;DR

This study demonstrates that epitaxial SrMoO3 thin films exhibit tunable plasmonic properties with low optical losses, making them promising for optical and plasmonic applications in the visible to near-infrared spectrum.

Contribution

The paper reports the first demonstration of tunable epsilon near zero wavelength in SrMoO3 thin films through strain engineering, with low optical losses compared to gold.

Findings

Tunable ENZ wavelength between 600 and 950 nm achieved.

SrMoO3 exhibits lower optical losses than gold at specific permittivity points.

Low electrical resistivity of 100E-6 Ohm cm at room temperature.

Abstract

Strontium molybdate (SrMoO3) thin films are shown to exhibit plasmonic behaviour with a zero crossover wavelength of the real part of the dielectric permittivity tunable between 600 and 950 nm (2.05 eV and 1.31 eV). The films are grown epitaxially on strontium titanate (SrTiO3), magnesium oxide (MgO), and lanthanum aluminate (LaAlO3) substrates by pulsed laser deposition. SrMoO3 is shown to have optical losses lower than those of gold at the point at which the real part of the dielectric permittivity is equal to -2, while possessing low electrical resistivity of 100E-6 Ohm cm at room temperature. Spectroscopic ellipsometry measurements reveal that SrMoO3 shows plasmonic behaviour, moreover we demonstrate that the epsilon near zero (ENZ) wavelength is tunable by engineering the residual strain in the films. The relatively broadband ENZ behaviour observed in SrMoO3 demonstrates its potential suitability for transformation optics along with plasmonic applications in the visible to near infrared spectral range.