fig3

Figure 3. (A) Calculated Grüneisen parameter γ of SnSe and NaSn₂SbSe₄ at 300 K; (B) Decomposition of 3ph scattering phase space (W_3ph) of NaSn₂SbSe₄ at 300 K into combination (λ + λ′ → λ″) and splitting (λ → λ′ + λ″) processes; (C) Decomposition of the 4ph scattering phase space (W_4ph) of NaSn₂SbSe₄ at 300 K into redistribution (λ + λ′ → λ″+ λ‴), recombination (λ + λ′+ λ″ → λ‴), and splitting (λ → λ′ + λ″+ λ‴) processes; (D) Decomposition of 4ph scattering rates of NaSn₂SbSe₄ at 300 K into the normal and Umklapp processes.