Discovering new materials with high breakdown strength is of great significance for scientific research and industrial applications. Here, we combine experiments and density functional theory (DFT) calculations to report a systematic study of two titanosilicates - A₂TiSi₂O₈ (A = Br, Sr) as a family of functional materials with wide band gaps, ultrahigh breakdown strength, and high thermal stability. The A₂TiSi₂O₈ materials possess ultrahigh electric breakdown (E_b >200 kVmm⁻¹, at 200 ℃), and good temperature stability (the variation of capacitance 3 %, from −100 to 200 ℃). DFT results show that electrons are likely localized in the SiO and TiO polyhedrons. The electron difference density map and density of states (DOS) results elucidate the wide band gaps in titanosilicate family due to the strong SiO and TiO bonds, indicating that the semiconductive behaviors are similar. The temperature-dependent structural evolution (from −100 to 500 ℃) is investigated via in-situ Raman spectroscopy.

发现具有高击穿强度的新材料对于科学研究和工业应用具有重要意义。在这里，我们结合实验和密度泛函理论（DFT）计算，报告了对两种钛硅酸盐-A ₂ TiSi ₂ O ₈（A = Br，Sr）作为具有宽带隙，超高击穿强度，和高热稳定性。A ₂ TiSi ₂ O ₈材料具有超高电击穿（E _b > 200 kVmm ^-1，在200℃时），以及良好的温度稳定性（在-100至200℃时电容变化3％）。DFT结果表明，电子很可能位于Si O和Ti O多面体中。电子差密度图和状态密度（DOS）结果阐明了钛硅酸盐家族的宽带隙，这归因于强的Si O和Ti O键，这表明半导体行为是相似的。通过原位拉曼光谱研究了温度依赖性的结构演化（从-100到500℃）。