Title: Noval Si-C Compounds with High Thermal Conductivity under TPa in Planetary Interior Show Chinese title

Title: 太阳系内部高压下具有高热导率的新型Si-C化合物

Abstract: Silicon carbide has excellent physical properties, such as high stability, thermal conductivity, and mechanical strength. It has been widely used in high-power devices, catalysis, material processing, and other fields and is of great significance in basic discipline research. We used crystal structure search and first principles calculation to predict four new silicon carbide structures stabilized within 3TPa. Pnma (SiC) replaces B1 (SiC) above 2.6TPa, and the new component Si3C2 becomes the most stable after 2.5TPa. P4/mbm phase Si3C2 under high pressure has electrode characteristics. The silicon-carbide structure is metallic in the study pressure range, and the electrons contribute most of the thermal conductivity, which is of great significance for the thermal evolution of silicon-carbide-like terrestrial planets. In addition, we propose a new silicon carbide planetary model and calculate the sound velocity of Si3C2 under TPa. Therefore, our research has deepened the understanding of silicon-carbide terrestrial planets' internal structure and thermal evolution, explored the complex silicon-carbide phase space, and enriched the silicon-carbide phase diagram. Show Chinese abstract

Abstract: 碳化硅具有优异的物理性能，如高稳定性、热导率和机械强度。 它已被广泛应用于高功率器件、催化、材料加工等领域，在基础学科研究中具有重要意义。 我们使用晶体结构搜索和第一性原理计算预测了四种在3TPa内稳定的新碳化硅结构。 Pnma (SiC) 在超过2.6TPa时取代B1 (SiC)，而新组分Si3C2在超过2.5TPa后成为最稳定的。 P4/mbm相 Si3C2在高压下具有电极特性。 在研究的压力范围内，碳化硅结构是金属的，电子贡献了大部分热导率，这对类似地球行星的碳化硅的热演化具有重要意义。 此外，我们提出了一种新的碳化硅行星模型，并计算了TPa下的Si3C2声速。 因此，我们的研究深化了对碳化硅类地行星内部结构和热演化的理解，探索了复杂的碳化硅相空间，丰富了碳化硅相图。