Fig. 2: Dielectric properties of α-Ti2O3 crystal.
From: Ultra-flat and long-lived plasmons in a strongly correlated oxide
a Schematic diagrams of type-I and type-II hyperbolic materials. b Real and imaginary parts of the permittivity along the xy-plane and the z- direction, collected by ellipsometry at room temperature. c Real and imaginary parts of the permittivity of α-Ti2O3 obtained from first-principles calculations. d Real and imaginary parts of the permittivity contributed exclusively by interband transitions. The pink shaded regions show the hyperbolic frequency windows, where the real parts of ε|| and ε⊥ have opposite signs. The data indicated by the solid (dashed) lines are results with (without) LFE. Source data are provided as a Source Data file.
