Indirect nuclear exchange and electronic structure of Tl2Te3 semiconductor: 203Tl and 205Tl NMR study

A Nuclear Magnetic Resonance (NMR) study of semiconductor Tl2Te3, in which Tl atoms are placed in galleries formed by puckered Te layers, is presented. Thallium NMR shows significant indirect exchange coupling between nuclei due to the overlap of electron wave functions of Tl atoms, mainly across the Te atoms. The analysis of this exchange interaction and the Tl chemical shielding provides us with knowledge about the nature of wave functions forming valence and conduction bands, the origin of interaction between Te and Tl orbitals and their hybridization. The comparison of our results with the calculation of the electronic structure and density of states of Tl2Te3 shows that the calculations are in good agreement with the conclusions based on NMR data.