Investigation of thermal conductivity and Raman spectra for HfAlB, TaAlB, and WAlB based on first-principles calculations

The Raman spectra, thermal conductivity, and related physical properties of three MAB materials HfAlB, TaAlB, and WAlB are investigated by using first-principles calculations. The results reveal that all three materials possess a metallic layered structure, characterized by alternating stacks of network layers composed of transition metals M, B, and Al layers. The strong covalent bonds between B atoms and the metallic bonds of M−Al collectively determine the stability and electrical conductivity of these materials. In terms of lattice thermal conductivity, TaAlB (34.0 W/(m K)) and HfAlB (16.9 W/(m K)) exhibit relatively high values, while WAlB (3.5 W/(m K)) shows significantly smaller thermal conductivity due to enhanced phonon scattering resulting from strong anharmonicity. Raman spectroscopic analysis reveals the presence of nine Raman-active modes in each material. The peaks at low frequencies correspond to the vibrational modes of M and Al atoms, whereas the peaks at high frequencies are associated with the stretching vibrations of covalent bonds within B atoms. Furthermore, HfAlB and TaAlB demonstrate reduced phonon scattering, which aligns with their thermal conductivity results. Notably, this study elucidates the intrinsic relationships among atomic structures, chemical bonds, and thermal transport properties, thereby providing a theoretical foundation for the use of MAB materials in high-temperature applications, including thermal conduction and thermal barrier coatings.