Synthesis, Structure, and Properties of Clathrate Si30.3(8)P15.7(8)Se7.930(3). Issue 40 (19th May 2017) - Zhang, Hui
Abstract: The new clathrate single crystal Si30.3(8) P15.7(8) Se7.930(3) was synthesized through a solid‐state reaction, and it was characterized to have a unit cell parameter a= 19.7614(1) Å and belong to space group Fm 3 ‾ . In this clathrate structure, a Se1−Si3 bond forms in place of the tetrakaidecahedron structure, and pental dodecahedral cages composed of Si and P atoms encapsulate Se2, Se3, and Se4 guest atoms. Similar structures are observed in partial Te‐ and Ge‐substituted compounds. Theoretical calculations based on an ordered formula Si32 P14 Se7 showed a semiconducting electronic structure with a band gap of 0.711 eV. A photoelectric response was observed in this compound at room temperature. Across the whole temperature range, this material exhibited a weak temperature‐dependent diamagnetic signal, and no phase transition or thermal anomaly was observed in heat capacity measurements. Abstract : Semiconducting materials : Si30.3(8) P15.7(8) Se7.930(3) and partial Te/Ge‐substituted semiclathrates were synthesized and characterized (see figure). Theoretical calculations showed a semiconducting feature based on an ordered model of Si32 P14 Se7, and photoelectric response and diamagnetism were observed in Si30.3(8) P15.7(8) Se7.930(3) .