Can we really trust ab initio thermal conductivity calculations?
Year: 2026
Type: preprint
Abstract: The lattice thermal conductivity (κ) is a key property governing heat transport in materials and plays a central role in applications ranging from thermoelectric to thermal management in electronics and energy technologies. Parameters-free first-principles calculations based on density functional theory (DFT) combined with the Peierls-Boltzmann transport equation (PBTE) have become a standard approach for predicting κ, and several independent open-source solvers are now available to the community. However, despite the widespread use of these tools, systematic cross-code validation studies remain limited. Here we present a comprehensive comparison of five widely used PBTE solvers -- ShengBTE, almaBTE, phono3py, elphbolt, and Phoebe -- applied to a diverse set of bulk materials spanning a wide range of κ. To ensure a fair comparison, the same ab initio data are used as input for all codes, eliminating DFT as a possible source of discrepancy. We find significant variability in the κ predictions, especially for low-κ materials, which has profound consequences for thermoelectric materials discovery. Finally, we propose a set of standard guideline for the developers of phonon BTE solvers in order to avoid common pathologies and pitfalls.
Source: HAL
Institution: Humboldt-Universität zu Berlin
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204738118
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