ORIGINAL PAPER Transportation behavior due to particular oxygen site vacancies in rutile TiO 2 N T Tayade 1 , M P Tirpude 2 * and P R Arjunwadkar 1 1 Department of Physics, Institute of Science, R T Road, Civil Lines, Nagpur, Maharashtra 440001, India 2 Department of Physics, Annasaheb Vartak College of Arts, K.M College of Commerce and E.S. Andrades College of Science, University of Mumbai, Vasai West, Dist Palghar, Maharashtra 401202, India Received: 27 July 2018 / Accepted: 15 March 2019 Abstract: This paper is dealing with the rutile structure of TiO 2 and the effect due to the vacancy of oxygen at a particular site by the first-principle calculation. The geometric places of oxygen site and the attribution of single and double sites were investigated in this study. The TiO 2 with selected site vacancies of oxygen can be treated as TiO 2-d (the form of defects in rutile). The DFT calculations have been done for the spin polarization. The Boltzmann transportation theory was applied to investigate the transport properties for temperature from 80 to 1000 K. Great variations have been observed in parameters (thermal and electric conductivities, Seebeck coefficient and Hall coefficient) in terms of the functions of temperature. The paper described how the particular site vacancy of oxygen plays a significant role. Keywords: Rutile TiO 2 ; First-principle calculation DFT; Boltzmann transportation properties; Oxygen site vacancy; Defect TiO 2-d PACS Nos.: 63.20.dk; 71.15.Mb; 72.80.-r; 66.70.Df; 72.20.-I; 72.25.Dc; 31.15.E- 1. Introduction The TiO 2 has a large band gap [1, 2], which shows semi- conducting [3, 4] (belonging to the group IV–VI semicon- ductors) nature and thermoelectric [5–7] characteristic behavior. TiO 2 is utilized as a crucially applicable material as photocatalysis [8] in several areas like environment pro- tection as a self-cleaning material [9], energy production [10] by water splitting [11], water purification microorgan- isms inactivation [12], etc. The electron transport properties of rutile TiO 2 photocatalyst have been reported [13]. In TiO 2 , the transportation of electrons is affected by temper- ature. The issue we raised is that, what would be the trans- portation property in the absence of oxygen in rutile TiO 2 at the particular sites (i.e., in a condition of a defect in struc- ture). A semiconducting TiO 2-d (where d is vacancy) has already reported the controlled addition of anion defects under the oxygen-deficient atmosphere at room temperature in which carriers (n) and density of spins have been calculated [14]. From this, the double exchange interaction is found active. It suggests that the magnetism is originating. The other structural defects in rutile TiO 2 (including oxygen vacancy) were also investigated using the first-principle study in the literature [15]. G. C. Va ´squez et al. have demonstrated the suitability of generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE) functional for the DFT analysis of the V O 2? defects in rutile TiO 2 [16]. They have shown the presence of empty elec- tronic states shifted by * 1 eV at the conduction band from t 2g and e g states can be associated with local distortions induced by V O 2? defects. Experimentally, Jinke Tang et al. have shown that the thermal conductivity (j) at 390 K (in Hydrogen) decreases with increasing annealed temperature (ranging from 750 to 1170 °C) due to the reduction in oxygen contents [17]. They have reported the j experi- mentally as 6 W K -1 m -1 for slightly reduced (annealed at 759 °C) to 0.83 W K -1 m -1 for heavily reduced (annealed at 1170 °C) Titania. The decreasing j means restricting the heat flow which is due to defects [18, 19]. This is responsible for the changes in parameters like specific heat, electrical conductivity, Seebeck coefficient and Hall coefficient. The possibility of different j is not ignorable for the same *Corresponding author, E-mail: mptirpude@rediffmail.com Indian J Phys https://doi.org/10.1007/s12648-019-01506-7 Ó 2019 IACS