2023/04/13 by Janak Tiwari, Tiwari, Janak, Tianli Feng +1 · 2 citations
Materials Science · Physics and Astronomy · #Boron and Carbon Nanomaterials Research #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Superconductivity in MgB2 and Alloys #Thermal properties of materials
paper · pdf · doi:10.48550/arxiv.2304.06805
openalex publication_date 2023/04/13 · openalex created_date 2023/04/19 · openalex updated_date 2026/08/01
Current phonon transport theory based on ground-state calculations has been successful in predicting thermal conductivity at room and medium temperatures but may misrepresent behavior at high temperatures. In this work, we predict the thermal conductivity (κ) of ZrC including electronic and phonon contributions from 300 K to 3500 K, by including high-order phonon scattering, lattice expansion, temperature-dependent (TD) harmonic and anharmonic force constants, and inter-band phonon conduction by using first principles. For the phonon transport, we find that four-phonon scattering significantly reduces the phonon thermal conductivity (κph), e.g., by ∼60% and ∼75% at 2500 K and 3500 K, respectively. After including four-phonon scattering and all other factors, κph shows a ∼T-1.5 rather than ∼T-1 dependence. The contribution from inter-band (Wigner) phonon conduction is small, even at ultra-high temperatures. The temperature dependence of anharmonic force constants decreases the phonon scattering cross-section at elevated temperatures and increases the κph significantly (by 52% at 3500 K). For the electronic thermal transport, we find that it is sensitive to and can be changed by 20% by the TD lattice constants. The Lorenz number varies from 1.6 to 3.3×10-8 W⋅Ω⋅K-2 at different temperatures. The theoretical prediction in the literature overpredicts κph (e.g., ∼28%) and underpredicts the κel (e.g., ∼38%), resulting in an overall underprediction of κ (∼26% at 1500 K). The impacts of grain size and defects are found strong, and no reported experimental data has reached the intrinsic theoretical thermal conductivity of ZrC yet.