TLS Spectral Density and Order-Disorder Transition Temperature in (KBr) 1−x (KCN) x

摘要: Low-temperature measurements (T ≃ 0.1 to 10K) of the thermal conductivity and specific heat [1–3] as well ultrasonic attenuation dispersion [4] on (KBr)1-x (KCN)x single crystals with 0 ∠ x 1 have revealed well-known acoustic anomalies found in a variety structurally disordered systems [5]. For = 0.25, 0.50 0.70, spectral density P two-level-systems (TLS) has been determined independently from time-dependence [3, 6] time scale texp 100µsec 10sec ultrasound data for longitudinal transverse modes (v 400MHz). By re-evaluating these we can now show that P(x)-values obtained by this method are good agreement those evaluated heat. From analysis evidence variation CN- concentration approximately ∝ (1-x)3.