Theoretical study of structural, mechanical, thermal and electronic properties of Ti₃B₄ with Ta₃B₄ structure under high pressure

We present a systematic theoretical study on the structural, electronic, elastic, and thermal properties of Ti₃B₄ in Ta₃B₄ structure under pressure. Our calculations indicate that the volume of Ti₃B₄ cell decreases about 12% of primary structure and the b axis length is shorten by 5% when the applied pressure is 36 GPa. The peak heights of DOS and PDOS curves of Ti₃B₄ are lower slightly when under high pressure. The calculated elastic constants and elastic modulus are all found to increase linearly by increasing pressure; and the heat capacity at constant volume (C_V) as a function of pressure are evaluated, which is more sensitive to the temperature than to the pressure. Meanwhile, the elastic anisotropy, phonon dispersion and corresponding phonon density of states with pressure are also calculated and discussed. The average LTEC of Ti₃B₄ is evaluated to be 8.6 × 10^-6 K^-1 at room temperature, which may provide valuable datum for its thermal property investigation.