Comparison between optoelectronic spectra and NMR shielding in tellurium based compounds: a FP-LAPW study

The Nuclear Magnetic Resonance (NMR) of 125 Te atom and optoelectronic spectra in the X 2 TeO 3 (X = Na, K, Ag) and PbTeO 3 compounds are investigated by the modified Becke-Johnson (mBJ) potential. Obtained magnetic shielding and the experimental chemical shifts are in close agreement. The X ions control polarity of the magnetic shielding around the 125 Te nucleus and σ iso (X) increases from Na 2 TeO 3 to PbTeO 3 compounds. Calculated band gap of X 2 TeO 3 (X = Na, K, Ag) and PbTeO 3 compounds are 3.23, 0.24, 3.63 and 3.95 eV, respectively. Density of states results show that the X 1,2 - p states in the bottom of the valence band have an essential role in the value of 125 Te NMR chemical shielding. The magnetic shielding of X atoms governs on the optical properties, such as the static dielectric function, refractive indexes and plasmon energies.