TY - JOUR
T1 - Comparative study of structural and electronic properties of TiO 2 at GGA and GGA+U level
AU - Mahmood, Tariq
AU - Cao, Chuanbao
AU - Ahmed, R.
AU - Saeed, M. A.
AU - Ahmed, Maqsood
PY - 2014
Y1 - 2014
N2 - Besides the structural properties, electronic bandstructure investigations of two technologically important phases (anatase and rutile) of titanium dioxide (TiO2) are studied in this research using DFT based first-principles plane-wave ultrsoft pseudo-potential (PW-PP) scheme of calculations as implemented in CASTEP computational code. In these Computations, for exchange-correlation functional, Perdew-Burke-Ernzerhof (PBE) parameterized generalized gradient approximation (GGA) and GGA+U are implemented, where 'U' is Hubbard correction parameter for screening self interaction. Optimum value of U applied in this study for rutile is 7.5eV, and for anatase is 9.0eV. Our calculated values of bandgap energy with PBE-GGA for anatase and rutile structure are 2.140eV and 1.973eV respectively which are sufficiently underestimated in comparison with experimental measurements whereas computed bandgap energy values within the implementation of GGA+U are found to be 3.350eV and 2.557eV respectively. These results are in nice agreement to experiment. Furthermore, to obtain the equilibrium volume, bulk modulus and pressure derivative, equation of state calculations were taken into account. Our calculated results for structural properties for anatase (V0=141.7 3, B0=417.4GPa and 0B =3.97,and rutile (V0=65.683, B0=153.24GPa and '0B =3.7) phases agree well with experimental as well as previously reported first principles studies.
AB - Besides the structural properties, electronic bandstructure investigations of two technologically important phases (anatase and rutile) of titanium dioxide (TiO2) are studied in this research using DFT based first-principles plane-wave ultrsoft pseudo-potential (PW-PP) scheme of calculations as implemented in CASTEP computational code. In these Computations, for exchange-correlation functional, Perdew-Burke-Ernzerhof (PBE) parameterized generalized gradient approximation (GGA) and GGA+U are implemented, where 'U' is Hubbard correction parameter for screening self interaction. Optimum value of U applied in this study for rutile is 7.5eV, and for anatase is 9.0eV. Our calculated values of bandgap energy with PBE-GGA for anatase and rutile structure are 2.140eV and 1.973eV respectively which are sufficiently underestimated in comparison with experimental measurements whereas computed bandgap energy values within the implementation of GGA+U are found to be 3.350eV and 2.557eV respectively. These results are in nice agreement to experiment. Furthermore, to obtain the equilibrium volume, bulk modulus and pressure derivative, equation of state calculations were taken into account. Our calculated results for structural properties for anatase (V0=141.7 3, B0=417.4GPa and 0B =3.97,and rutile (V0=65.683, B0=153.24GPa and '0B =3.7) phases agree well with experimental as well as previously reported first principles studies.
KW - Bandgap
KW - CASTEP
KW - Wide gap semiconductors
UR - http://www.scopus.com/inward/record.url?scp=84894610818&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:84894610818
SN - 1454-4164
VL - 16
SP - 117
EP - 122
JO - Journal of Optoelectronics and Advanced Materials
JF - Journal of Optoelectronics and Advanced Materials
IS - 1-2
ER -