Sains Malaysiana 42(2)(2013): 231–237

Pressure Induced Structural and Electronic Bandgap Properties of Anatase and Rutile TiO₂

(Struktur dan Tekanan Ciri Jurang Jalur Elektronik Anatas dan TiO₂ Rutil yang dirangsang oleh Tekanan)

Tariq Mahmood^1,2*, Chuanbao Cao¹, Rashid Ahmed³, Maqsood Ahmed², M. A. Saeed³, Abrar Ahmed Zafar², Talab Husain² & M.A. Kamran¹

¹School of Materials Science and Engineering, Beijing Institute of Technology, Beijing-100081 

P.R. China

²Centre for High Energy Physics, University of the Punjab, Lahore-54590, Pakistan

³Physics Department, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor

Malaysia

Received: 7 January 2012 / Accepted: 21 May 2012

ABSTRACT

In this study, we present the structural and electronic bandgap properties of anatase and rutile titanium dioxide by applying ultrasoft pseudo-potential plane wave approach developed within the frame of density functional theory (DFT). We used generalized gradient approximation (GGA) proposed by Perdew-Burke-Ernzerhof (PBE) for exchange correlation potential. In our pressure driven investigations, geometry optimization is carried out for different values of pressure over a range of 0-100 GPa and subsequently related structural parameters and bandgap values of anatase and rutile titanium dioxide (TiO₂) have been calculated. In both cases, the lattice constants (a, c) and volume decreased as the pressure was increased. Similarly, internal parameter for anatase increased and for rutile TiO₂ it decreased under high pressure. The value of c/a decreased for anatase and increased for rutile TiO₂ as a function of pressure. Our band structure analysis showed different behavior of bandgap between anatase and rutile TiO₂. The conduction band of anatase TiO2 moved opposite to the conduction band of rutile TiO₂ as we increased the pressure. Additionally we used the Birch-Murnaghan equation of state to obtain the equilibrium volume (V0), bulk modulus (B0) and pressure derivative of bulk modulus (B0’) at zero pressure. The calculated results are in good agreement with previous experimental as well as theoretical results.

Keywords: Conduction band; density function theory; pressure

ABSTRAK

Di dalam kajian ini, kami membentangkan ciri struktur dan jurang jalur elektronik bagi anatas dan titanium dioksida rutil dengan menggunakan pendekatan gelombang satah pseudo-keupayaan ultralembut yang dibangunkan dalam kerangka teori fungsi ketumpatan (DFT). Kami menggunakan penganggaran ceruk umum (GGA) yang diusulkan oleh Perdew-Burke-Ernzerhof (PBE) untuk keupayaan korelasi pertukaran. Kajian tekanan yang didorong pengoptimuman geometri telah dijalankan untuk nilai tekanan yang berbeza pada julat 0-100 GPa. Parameter struktur dan nilai jurang jalur anatas dan titanium dioksida rutil telah dikira. Dalam kedua-dua kes, nilai pemalar kekisi (a, c) dan isi padu menurun apabila tekanan meningkat. Parameter dalaman untuk anatas meningkat dan untuk TiO₂ rutil menurun pada tekanan tinggi. Nilai c/a menurun untuk anatas dan meningkat untuk TiO₂ rutil sebagai fungsi tekanan. Analisis struktur jalur menunjukkan tingkah laku yang berbeza antara jurang jalur anatas dan TiO₂ rutil. Jalur konduksi anatas TiO₂ bergerak dengan berlawanan arah terhadap jalur konduksi TiO₂, rutil apabila tekanan meningkat. Persamaan keadaan Birch-Murnaghan telah digunakan untuk mendapatkan isi padu keseimbangan (V0) modulus pukal (B0) dan terbitan tekanan modulus pukal (B0’) pada tekanan sifar. Keputusan yang diperoleh adalah selari dengan keputusan uji kaji dan teori yang sebelumnya.

Kata kunci: Jalur konduksi; tekanan; teori fungsi ketumpatan

REFERENCES

Arlt, T., Bermejo, M., Blanco, M.A., Gerward, L., Jiang, J.Z., Staun Olsen, J. & Recio, J.M. 2000. High-pressure polymorphs of anatase TiO2. Phys. Rev. B 61(21): 14414-14419.

Asahi, R., Taga, Y., Mannstadt, W. & Freeman, A.J. 2000. Electronic and optical properties of anatase TiO2. Phys. Rev. B 61(11): 7459-7465.

Asahi, R., Morikawa, T., Ohwaki, T., Aoki, K. & Taga, Y. 2001. Visible-light photocatalysis in nitrogen-doped titanium oxides. Science 293: 269-271.

Baizaee, S.M. & Mousavi, N. 2009. First-principles study of the electronic and optical properties of rutile TiO2. Phyica B 404: 2111-2116.

Burdett, J.K., Hughbanks, T., Miller, G.J., Richardson, J.W. Jr. & Smith, J.V. 1987. Structural-electronic relationships in inorganic solids: Powder neutron diffraction studies of the rutile and anatase polymorphs of titanium dioxide at 15 and 295 K. J. Am. Chem. Soc. 109(12): 3639-3646.

Carp, O., Huisman, C.L. & Reller, A. 2004. Photoinduced reactivity of titanium dioxide. Prog. Solid State Chem. 32(1-2): 33-177.

Chen, Q. & Cao, H-H. 2004. Ab initio calculations of electronic structure of anatase TiO2 Chinese Physics B 13(12): 2121.

Cho, E., Han, S., Ahn, H-S., Lee, K-R., Kim, S.K. & Hwang, C.S. 2006. First-principles study of point defects in rutile TiO2−x. Phys. Rev. B 73(19): 193202.

Di Valentin, C., Pacchioni, G. & Selloni, A. 2004. Origin of the different photoactivity of n-doped anatase and rutile TiO2. Phys. Rev. B 70(8): 085116.

Di Valentin, C., Pacchioni, G., Selloni, A., Livraghi, S. & Giamello, E. 2005. Characterization of paramagnetic species in n-doped TiO2 powders by EPR spectroscopy and DFT calculations. J. Phys. Chem. B 109: 11414-11419.

Diebold, U. 2003. The surface science of titanium dioxide. Surf. Sci. Rep. 48(5-8): 53-229.

Diwald, O., Thompshon, T.L., Zubkov, T., Goralski, E.G., Walck, S.D. & Yates, J.T. Jr. 2004. Photochemical activity of nitrogen-doped rutile TiO2(110) in visible light. J. Phys. Chem. B 108(19): 6004-6008.

Fische, T.H. & Almlof, J. 1992. General methods for geometry and wave function optimization. J. Phys. Chem. 96: 9768-9774.

Fox, H., Newman, K.E., Schneider, W.F. & Corecelli, S.A. 2010. Bulk and surface properties of rutile TiO2 from self-consistent-charge density functional tight binding. J. Chem. Theory Comput. 6: 499-507.

Fujishima, A. & Honda, K. 1972. Electrochemical photolysis of water at a semiconductor electrode. Nature 238(5358): 37-38.

Gole, J.L., Stout, J.D., Burda, C., Lou, Y. & Chen, X. 2004. Highly efficient formation of visible light tunable TiO2-xNx photocatalysts and their transformation at the nanoscale. J. Phys. Chem. B 108(4): 1230-1240.

Griffin, G.L. & Siefering, K.L. 1990. Growth kinetics of CVD TiO2: Influence of carrier gas. J. Electrochem. Soc. 137(4): 1206-1208.

Irie, H., Watanabe, Y. & Lindquist, S-E. 2003. Nitrogen-concentration dependence on photocatalytic activity of TiO2-xNx powders. J. Phys. Chem. B 107(23): 5483-5486.

Islam, M.M., Bredow, T. & Gerson, A. 2007. Electronic properties of oxygen-deficient and aluminum-doped rutile TiO2 from first principles. Phys. Rev. B 76(4): 045217.

Iuga, M., Steinle-Neumann, G. & Meinhardt, J. 2007. Ab-initio simulation of elastic constants for some ceramic materials. Eur. Phys. J. B 58: 127-133.

Janisch, R., Gopal, P. & Spaldin, N.A. 2005. Transition metal-doped TiO2 and ZnO-present status of the field. J. Phys.: Condens. Matter 17(27): R657.

Khan, S.U.M., Al-Shahry, M. & Ingler, W.B. Jr. 2002. Efficient photochemical water splitting by a chemically modified n-TiO2. Science 297(5590): 2243-2245.

Labat, F., Baranek, P., Domain, C., Minot, C. & Adamo, C. 2007. Density functional theory analysis of the structural and electronic properties of TiO2 rutile and anatase polytypes: Performances of different exchange-correlation functional. J. Chem. Phys. 126(15): 154703.

Lazzeri, M., Vittadini, A. & Selloni, A. 2001. Structure and energetics of stoichiometric TiO2 anatase surfaces. Phys. Rev. B 63(15): 155409.

Lin, Zh., Orlov, A., Lambert, R.M. & Payne, M.C. 2005. New insights into the origin of visible light photocatalytic activity of nitrogen-doped and oxygen-deficient anatase TiO2. J. Phys. Chem. B 109(44): 20948-20952.

Lindgren, T., Mwabora, J.M., Avendano, E., Jansson, J., Hoel, A., Granqvist, C-G. & Lindquist, S-E. 2003. Photoelectrochemical and optical properties of nitrogen doped titanium dioxide films prepared by reactive DC magnetron sputtering. J. Phys. Chem. B 107(24): 5709-5716.

Liu, Y., Ni, L., Ren, Z., Xu, G., Song, C. & Han, G. 2009. Negative pressure induced ferroelectric phase transition in rutile TiO2. J. Phys.: Condens. Matter 21(27): 275901.

Ma, X.G., Liang, P., Miao, L., Bei, S.W., Zhang, C.K., Xu, L. & Jiang, J.J. 2009. Pressure-induced phase transition and elastic properties of TiO2 polymorphs. Phys. Status Solidi B 246(9): 2132-2139.

Mattioli, G., Filippone, F., Alippi, P. & Bonapasta, A.A. 2008. Ab initio study of the electronic states induced by oxygen vacancies in rutile and anatase TiO2. Phys. Rev. B 78(24): 241201.

Monkhorst, H.J. & Pack, J.D. 1976. Special points for Brillouin-zone integrations. Phys. Rev. B 13: 5188-5192.

Murnaghan, F.D. 1944. The compressibility of media under extreme pressures. Proc. Natl. Acad. Sci. USA 30(9): 244-247.

Nakamura, R., Tanaka, T. & Nakato, Y. 2004. Mechanism for visible light responses in anodic photocurrents at n-doped TiO2 film electrodes. J. Phys. Chem. B 108(30): 10617-10620.

Pascual, J., Camassel, J. & Mathieu, H. 1978. Fine structure in the intrinsic absorption edge of TiO2. Phys. Rev. B 18(10): 5606-5614.

Perdew, J.P., Burke, K. & Ernzerhof, M. 1996. Generalized gradient approximation made simple. Phys. Rev. Lett. 77: 3865-3868.

Persson, C. & da Silva, A.F. 2005. Strong polaronic effects on rutile TiO₂ electronic band edges. Appl. Phys. Letts. 86(23): 231912.

Sakthivel, S. & Kisch, H. 2003. Photocatalytic and photoelectrochemical properties of nitrogen-doped titanium dioxide. ChemPhysChem 4(5): 487-490.

Segall, M.D., Lindan, P., Probet, M.J., Pickard, C.J., Hasnip, P.J., Clark, S.J. & Payne, M.C. 2002. First-principles simulation: Ideas, illustrations and the CASTEP code. J. Phys. Condens. Matter 14: 2717-2744.

Shi, H., Luo, W., Johansson, B. & Ahujia, R. 2009. Electronic and elastic properties of CaF2 under high pressure from ab initio calculations. J. Phys. Condens. Matter 21(41): 415501.

Shirley, R., Kraft, M. & Inderwildi, O.R. 2010. Electronic and optical properties of aluminium-doped anatase and rutile TiO₂ from ab initio calculations. Phys. Rev. B 81: 075111.

Swamy, V. & Muddle, B.C. 2007. Ultrastiff cubic TiO₂ identified via first-principles calculations. Phys. Rev. Lett. 98(3): 035502.

Tang, H., Berger, H., Schmid, P.E., Levy, F. & Burri, G. 1993. Photoluminescence in TiO₂ anatase single crystals. Solid State Commun. 87(9): 847-850.

Tariq Mahmood, Chuanbao Cao, Waheed S. Khan, Zahid Usman, Faheem K. Butt, Sajad Hussain. 2012. Electronic, elastic, optical properties of rutile TiO2 under pressure: A DFT study. Physica B: Condensed Matter 207: 958-965.

Thilagam, A., Simpson, D.J. & Gerson, A.R. 2011. A first-principles study of the dielectric properties of TiO2 polymorphs. J. Phys. Condens. Matter 23(2): 025901.

Varghese, O.K. & Grimes, C.A. 2003. Metal oxide nanoarchitectures for environmental sensing. J. Nanosci. Nanotech. 3(4): 277-293.

Wu, J.M. & Chen, C.J. 1990. Effect of powder characteristics on microstructures and dielectric properties of (Ba,Nb)-doped titania ceramics. J. Am. Ceram. Soc. 73(2): 420-424.

Yahya Al-Khatabeh, Kanani K.M. Lee and Boris Kiefer. 2009. High-pressure behavior of TiO2 as determined by experiment and theory. Phys. Rev. B 79(13): 134114.

Yin, W-J., Chen, S., Yang, J-H., Gong, X-G., Yan, Y. & Wei, S-H. 2010. Effective bandgap narrowing of anatase TiO₂ by strain along a soft crystal direction. Appl. Phys. Lett. 96(22): 221901.

Zhao, W., Ma, W., Chen, Ch., Zhao, J. & Shuai, Zh. 2004. Efficient degradation of toxic organic pollutants with Ni₂O₃/TiO₂-xBx under visible irradiation. J. Am. Chem. Soc. 126(15): 4782-4783.

Zhou, X-F., Dong, X., Qian, G-R., Zhang, L., Tian, Y. & Wang, H-T. 2010. Unusual compression behavior of TiO₂ polymorphs from first principles. Phys. Rev. B 82(6): 060102(R).

*Corresponding author; email: tariq_mahmood78@hotmail.com