The elastic, electronic, and optical properties ofTi O21: studying of GGA(LDA)+U

Based on the first-principles of density functional theory, the elastic, electronic and optical properties of three titanium suboxides TinO2n-1(n=5,6 and 7) are calculated and analyzed using generalized gradient approximation (GGA+U) and local density approximation (LDA+U) under the pseudopotential of ultra-soft. The results show that all three titanium suboxides are elastically anisotropic, but Ti5O9 has the smallest anisotropy. All the three materials exhibit certain ductility and have certern hardness (~10 GPa). Electronic structure analysis indicates that Ti5O9, Ti6O11 and Ti7O13 have half-metallic properties, while Ti5O9 also has magnetic property, that is mainly derived from the 3d orbit electrons of Ti atoms. Optical property analysis shows that in the far ultraviolet region (6~12 eV), the reflection coefficient, absorption coefficient and extinction coefficient form resonance.