Raman Spectra and Thermal Conductivity of TiAlB, VAlB, CrAlB: An Ab Initio Study

This paper systematically studies the electronic properties, Raman spectra, and thermal conductivity of MAB phase materials TiAlB, VAlB, and CrAlB using first-principles calculation methods with the VASP software package. The results show that TiAlB, VAlB, and CrAlB all belong to the orthorhombic Cmcm space group and have a layered structure. The electronic states near the Fermi level of TiAlB, VAlB, and CrAlB mainly originate from the 3d orbitals of transition metals and the p orbitals of B, exhibiting metallic conductivity. The phonon spectra of the three materials have no imaginary frequencies, and the optical branches are dominated by the high-frequency vibrations of light-mass B atoms. There are 18 vibrational modes at the center of the Brillouin zone for the three materials, including 6 infrared-active modes (B_1u, B_2u, B_3u) and 9 Raman-active modes (A_g, B_1g, B_3g). In terms of thermal conductivity, CrAlB exhibits a markedly higher lattice thermal conductivity (50.6 W/(m·K)) than TiAlB (8.6 W/(m·K)) and VAlB (5.8 W/(m·K)). This superiority stems from its smaller Grüneisen parameter, which signals weaker anharmonicity and fewer phonon-scattering channels, whereas the stronger anharmonicity in TiAlB and VAlB suppresses heat transport.