Structural change of liquid Si 15Te 85 and Si 20Te 80 with temperature: Ab initio molecular dynamics simulations

Abstract

Using ab initio molecular dynamics simulations, the structural and electronic properties of liquid Si 15Te 85 and Si 20Te 80 at two temperatures were studied respectively. Compared with available experimental data, the calculated structure factors are acceptable. From symmetry arguments, the calculated partial bond-angle distribution functions suggest that with increasing temperature the extensive tetrahedral network structures persist longer in liquid Si 20Te 80 than those do in liquid Si 15Te 85. Our results indicate that the local tetrahedral structure around Si atoms and the Peierls-like distorted local atomic structure around Te atoms both play important roles in the structural change of liquid Si 20Te 80 and Si 15Te 85, which also suggest that the mechanisms of the structural change upon cooling in liquid Si 20Te 80 and Si 15Te 85 are of no essential difference . The results of DOS and LDOS indicate that the variation of the dip in DOS at E F mainly results from the change of Te p orbitals.