First-principles calculations of the electronic structure and thermodynamic properties of B–Co–O materials

Abstract

In the present study, the structural properties, electronic, elastic, and thermodynamic properties of Co4B6O13、Co2B2O5、Co3(BO3)2、Co(BO2)2, and CoB4O7 materials were calculated by adopting first-principles calculation method based on density functional theory. The simulated lattice constant is compliant with the existing experimental data well. The formation energy, Gibbs free energy, and phonon dispersion curves show that the B–Co–O materials are thermodynamically stable. The results show that the mechanical properties of CoB4O7 material is excellent, while the mechanical properties of Co2B2O5 material is the weakest. The CoB4O7 material has higher Debye temperature and constant volume heat capacity, and the thermodynamic stability of Co3(BO3)2 is the best. By analyzing band structure and electronic density of states, Co2B2O5 and Co3(BO3)2 materials are conductors, Co4B6O13, Co(BO2)2 and CoB4O7 materials belong to P-type semiconductors. Through electronic density of states analysis and Hirshfeld analysis, they indicated that five B–Co–O materials exhibit ferromagnetic.