Structural, electronic, magnetic and hyperfine properties of V-doped SnO2 (Sn1-xVxO2, x: 0, 0.042, 0,084, 0.125). A DFT based ab initio study

H. H. MEDINA CHANDUVI; A. M MUDARRA NAVARRO; VITALIY BILOVOL; L. A. ERRICO; A. V. GIL REBAZA

Brasov

Conferencia; International Conference on the Applications of the Mössbauer Effect (ICAME); 2021

National Institute of Materials Physics (NIMP)

Based on Density-Functional Theory ab initio calculations we have investigated the effect of V doping on the structural, electronic and magnetic properties of rutile tin dioxide (Sn1-xVxO2) for different V concentrations x (x: 0.042, 0.084, 0.125). These concentrations are comparable to those experimentally studied. Calculations have been performed using two different and complementary methods: The pseudopotentials and plane-wave method (PP-PW) was used for the determination of the lowest energy distribution of the V impurities in the SnO2 host and the equilibrium lattice parameters for each x value, whilst the study of the electronic structure properties and hyperfine parameters at the Sn and V sites of Sn1-xVxO2 was carried out applying the Full Potential Linearized Augmented Plane-Wave method (FP-LAPW). In order to obtain a precise description of electronic structure and the band gaps of the doped oxide, in addition to the Local Spin Density and the General Gradient Approximations (LSDA and GGA, respectively), state-of-the-art exchange-correlation hybrid functional were employed: the Heyd-Scuceria-Ernserhof (HSE06) and the Tran-Blaha modified Becke-Johnson exchange potential (TB-mBJ). Our calculations showed that V in a 4+ oxidation state substitutionally replaces Sn4+ ions. The impurities induce a reduction of the cell volume of SnO2, in excellent agreement with the experimental results reported in the literature, and a shortening of the V-Oxygen nearest neighbours bond lengths (compared to the Sn-O nearest neighbours distances in pristine SnO2). A spin polarization at the V sites is predicted, giving rise to a magnetic moment of 0.85 μB per V atom being the magnetic ground state of the resulting system paramagnetic. TB-mBJ and HSE06 approaches accurately describe the experimentally reported dependence of the band gap with x, showing that the band gap of SnO2 can be tuned by means of an appropriate doping with V. Finally, our predictions for the hyperfine parameters at the Sn sites are in excellent agreement with 119Sn Mössbauer experimental results, given confidence to our results for the electronic structure of the Sn1-xVxO2 alloys. Hyperfine parameters at the V sites are also presented.