Atomic Mass Engineering of Ultra-High Thermal Conductivity in Large Bandgap Materials: A Case Study with Boron Arsenide

Abstract Heat dissipation highly relies on the thermal conductivity ( κ ) of materials. Materials with large bandgaps and significant atomic mass ratios, such as BAs, SiC, and θ -TaN, have attracted considerable attention due to their potential for achieving ultra-high κ , with BAs serving as a particularly representative example due to its unique combination of large bandgap and high thermal conductivity. In this paper, the effects of atomic mass modification on phonon bandgap and κ are systematically investigated using a BAs model, accounting for both three- and four-phonon scattering processes. A 20% increase in κ can be obtained by substituting B, achieved through widening the phonon bandgap, which suppresses phonon scattering. Notably, the AAOO four-phonon scattering channel is more suppressed than the AAO three-phonon channel, leading to an increased phonon lifetime ( τ ). For As, κ can also be enhanced by 5% when replaced by lighter atoms, such as 69 As, primarily due to the increased phonon group velocity ( v ). We systematically clarify how atomic-mass-induced bandgap variations affect τ , v , and therefore κ in wide-bandgap systems. Our work provides a specific scheme for further improving the ultra-high κ of materials with large bandgaps, which possesses great guiding significance.