Oscillations, Waves, and Interactions - GWDG

320 Martin Dressel
Absorptivity
σ 1 (Ω −1 cm −1 )
10 0
10 −1
10 −2
10 −3
10 3
10 2
10−1 101 K 0.3MoO 3
T = 300 K
E b
E⏐⏐b
E b
K 0.3MoO 3
10 0
E⏐⏐b
10 1 10 2 10 3
Frequency (cm −1 )
Cavity Pert.
Reflectivity
Reflectivity
Fit
DC Values
Cavity Pert. (300 K)
Cavity Pert. (200 K)
Fabry-Perot (300 K)
Fit (300 K)
Fit (200 K)
(a)
2∆ (b)
10 4 10 5
Figure 9. (a) Frequency dependence of the room temperature absorptivity A = 1 − R
of blue bronze (K0.3MoO3) in both orientations E � stacks and E ⊥ stacks. The squares
were obtained by measuring the surface resistance using cavity perturbation method, the
circles represent data of quasioptical reflectivity measurements employing a Fabry-Perot
resonator. The solid lines show the results of the dispersion analysis of the data. (b) Optical
conductivity of K0.3MoO3 measured parallel and perpendicular to the stacks by standard dc
technique (arrows), cavity perturbation (open squares), coherent-source THz spectroscopy
(solid dots) and infrared reflectivity. The open arrow indicates the single-particle gap as
estimated from dc measurements below TCDW (after Ref. [20]).