Multilevel Tunnelling Systems and Fractal Clustering in the Low-Temperature Mixed Alkali-Silicate Glasses

Table 1

Extracted parameters for the glasses; K-Si stands for the (SiO₂)_1−𝑥(K₂O)_𝑥 glasses. In all of the best fits, we have employed the values Δ_0min = 3.9 mK and Δ_0max = 10 K extracted from fitting the pure SiO₂ data of Figure 7 (inset).

Glass type	𝑥	𝐴2LS	𝛾	𝐴ATS	𝐷min	Γ
	mol	10^−5	10^−8 sJ^3	10^−5	K	10^−6 sK^5
SiO2	0	47.2	5.30	—	—	—
AlBaSiO	—	116.2	13.40	264.7	0.65	69.73
K-Si	0.05	104.1	1.33	75.5	0.87	3.55
K-Si	0.08	146.5	1.23	130.0	0.87	3.97
K-Si	0.10	158.5	1.15	160.0	0.87	5.08
K-Si	0.20	239.5	0.82	281.9	0.87	6.44