Fig. 1: Specific heat vs. temperature for Ag₃LiIr₂O₆ and α–LiIr₂O₃.

Measured values of the specific heat C(T) divided by temperature T (denoted by γ(T) ≡ C(T)/T) vs T for a Ag₃LiIr₂O₆ and c α–LiIr₂O₃, both with the Schottky contributions subtracted. We also give the plots of δ(T) ≡ (γ(T) − γ₀)/T for the same compounds (shown in b and d, respectively). The specific heat data for α–LiIr₂O₃ is taken from the work of Mehlawat, Thamizhavel, and Singh⁴¹. For plots of the raw data of the Ag₃LiIr₂O₆, see Figs. 6 and 7 in the Methods section. The data in a fit to a general quadratic, in agreement with Eqn. (1). However, the general temperature dependence for the specific heat in α–LiIr₂O₃, as shown in c, lacks the strong quadratic behavior predicted from Eqn. (1). The plotted values of δ(T) in b and d represent the same specific heat data, but plotted in such a way as to discern possible linear-T dependence. The blue dots (left axis) are the unrenormalized data of δ(T) defined in text, while the red dots (right axis) are the data renormalized by the projected T = 0 value. A finite y-intercept in b suggests a finite T/T_cut term in γ(T).