One-step synthesis of type-I silicon clathrate Ba8Si46 under high pressure and high temperature

Abstract

In this paper, the silicon clathrate [Formula: see text] was successfully synthesized using low-cost antioxidative azide [Formula: see text] and Si as precursors by means of high pressure and high temperature (HPHT). The clathrate phase was one-step synthesized by high pressure chemical method within a short time. The reaction temperature and pressure were optimized to achieve good-quality crystalline products with a composition of [Formula: see text] and its transition temperature [Formula: see text] is about 8.3 K. The new preparation route presented in this paper provides an alternative to the multistep HPHT synthesis applied so far. One-step synthesis of type-I silicon clathrate [Formula: see text] by high pressure chemical method can shorten the synthesis period of time greatly.