Figure 2: Optical conductivity spectra and spectral weight of pressure-dependent Sr1−xNbO3+δ films.
From: Tunable and low-loss correlated plasmons in Mott-like insulating oxides

(a) The optical conductivity, σ1(ω), of lp-SNO (5 × 10−6 Torr), mp-SNO (3 × 10−5 Torr) and hp-SNO (1 × 10−4 Torr) films. (b) Evolution of spectral weight, W, of three energy regions: W1 (0.6–2.0 eV), W2 (2.0–4.3 eV) and W3 (4.3–6.5 eV) across the three films. The Wtot is the total W from 0.6 to 6.5 eV.