  One route to create tunable metamaterials is through integration with
"on-demand" dynamic quantum materials, such as vanadium dioxide (VO2). This
enables new modalities to create high performance devices for historically
challenging applications. Indeed, dynamic materials have often been integrated
with metamaterials to imbue artificial structures with some degree of
tunability. Conversely, metamaterials can be used to enhance and extend the
natural tuning range of dynamic materials. Utilizing a complementary split ring
resonator array deposited on a VO2 film, we demonstrate enhanced terahertz
transmission modulation upon traversing the insulator-to-metal transition (IMT)
at ~340 K. Our complementary metamaterial increases the modulation amplitude of
the original VO2 film from 42% to 68.3% at 0.47 THz upon crossing the IMT,
corresponding to an enhancement of 62.4%. Moreover, temperature dependent
transmission measurements reveal a redshift of the resonant frequency arising
from a giant increase of the permittivity of the VO2 film. Maxwell-Garnett
effective medium theory was employed to explain the permittivity change upon
transitioning through the IMT. Our results highlight that symbiotic integration
of metamaterial arrays with quantum materials provides a powerful approach to
engineer emergent functionality.
