Fig. 3: Lattice thermal conductivity, phonon scattering rates and phase spaces.

a Calculated temperature-dependent averaged lattice thermal conductivity, including contributions from population and coherence conductivities, accounts for only 3 ph both 3 ph and 4 ph scattering processes. The light blue shaded area indicates the particle-like phonon propagation contributions, and the light green shaded area represents the wave-like phonon tunneling contributions. b Calculated averaged spectral and cumulative lattice thermal conductivity from particle-like phonon propagation channel considering only 3 ph, and both 3 ph and 4 ph scattering processes at 300 K. c Calculated 3 ph and both 3 ph and 4 ph scattering rates at 300 K, respectively. Here, the harmonic (2nd-) and anharmonic force constants (3rd- and 4th-order) are extracted at finite temperature (300 K). d Calculated population thermal conductivity at 300 K using phonon dispersions, with selective exclusion of specific phonon bands. Herein, elements of the scattering matrix involving the omitted modes are set to zero, isolating their effects on thermal transport.