  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.
