No abstract

We analyze the structure and dynamics of semiconducting liquid GeSe using ab initio molecular-dynamics simulations. We show the local order of the liquid to be close to that of the low-temperature crystalline phase, ␣-GeSe. In particular, we show that the Peierls distortion, which defines the ␣ phase and vanishes in the high-temperature ␤ crystalline phase, reenters GeSe in the melt. Examining the distance histograms allows one to analyze the Ge environment as consisting of a GeSe 3 unit and having one Ge-Ge defective bond. Evidence is presented that Peierls distortion is directly responsible for the semiconducting behavior of the melt. The calculated viscosity and electrical conductivity are in agreement with the experiment. An additional neutrondiffraction experiment indicates that this liquid structure is unmodified 200 K above the melting point.