Glass-like Transport Dominates Ultralow Lattice Thermal Conductivity in Modular Crystalline BiOSeCl.

Crystalline BiOSeCl exhibits record-low 0.1 W/mK lattice thermal conductivity (κ), but the underlying transport mechanism is not yet understood. Using a theoretical framework which incorporates first-principles anharmonic lattice dynamics into a unified heat transport theory, we compute both the particle-like and glass-like components of κ in crystalline and pellet BiOSeCl forms.

Intrinsically Low Thermal Conductivity in the Most Lithium-Rich Binary Stannide Crystalline LiSn.

Using lattice dynamics and a unified heat transport theory, we compute the lattice thermal conductivity (κ) of LiSn, a newly synthesized crystalline material for Li-ion batteries. The weak bonding in the Li-rich environment leads to significant softening of the optical phonon modes, temperature-induced hardening, and strong anharmonicity. This complexity is captured in the particle-like and glass-like components of κ by accounting for the temperature-dependent interatomic force constants acting on the renormalized phonon frequencies and three- and four-phonon scatterings contributing to the phonon lifetime.

Predicting the Lattice Thermal Conductivity in Nitride Perovskite LaWN from ab initio Lattice Dynamics.

Using a density functional theory-based thermal transport model, which includes the effects of temperature (T)-dependent potential energy surface, lattice thermal expansion, force constant renormalization, and higher-order quartic phonon scattering processes, it is found that the recently synthesized nitride perovskite LaWN displays strong anharmonic lattice dynamics manifested into a low lattice thermal conductivity (κ ) and a non-standard κ ∝T dependence. At high T, the departure from the standard κ ∝T law originates in the dual particle-wave behavior of the heat carrying phonons, which includes vibrations tied to the N atoms. While the room temperature κ =2.

Four-phonon and electron-phonon scattering effects on thermal properties in two-dimensional 2H-TaS.

Thermal transport characteristics of monolayer trigonal prismatic tantalum disulfide (2H-TaS) are investigated using first-principles calculations combined with the Boltzmann transport equation. Due to a large acoustic-optical phonon gap of 1.85 THz, the four-phonon (4ph) scattering significantly reduces the room-temperature phononic thermal conductivity ().