High pressure structural stability of the Na-Te system

High pressure structural stability of the Na-Te system

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The ab initio evolutionary algorithm is used to search for all thermodynamically stable Na-Te compounds at extreme pressure.In our calculations, several new structures are discovered at high pressure, namely, Imma Na2Te, click here Pmmm NaTe, Imma Na8Te2 and P4/mmm NaTe3.Like the known structures of Na2Te (Fm-3m, Pnma and P63/mmc), the Pmmm NaTe, Imma Na8Te2 and P4/mmm NaTe3 structures also show semiconductor properties with band-gap decreases when pressure increased.However, we find that the band-gap of Imma Na2Te structure increases with pressure.

We presume that the result may be caused by the increasing of splitting between Te p states and Na s, Na p and Te d states.Furthermore, we think that the strong hybridization between Na click here p state and Te d state result in the band gap increasing with pressure.