Dataset for "Colossal Cryogenic Electro-Optic Response Through Metastability in Strained BaTiO3 Thin Films"

Abstract: The search for thin film electro‐optic materials that can retain superior performance under cryogenic conditions has become critical for quantum computing. Barium titanate thin films show large linear electro‐optic coefficients in the tetragonal phase at room temperature, which is severely degraded down to ≈200 pm V−1 in the rhombohedral phase at cryogenic temperatures. There is immense interest in manipulating these phase transformations and retaining superior electro‐optic properties down to liquid helium temperature. Utilizing the thermodynamic theory of optical properties, a large low‐temperature electro‐optic response is designed by engineering the energetic competition between different ferroelectric phases, leading to a low‐symmetry monoclinic phase with a massive electro‐optic response. The existence of this phase is demonstrated in a strain‐tuned BaTiO3 thin film that exhibits a linear electro‐optic coefficient of 2516 ± 100 pm V−1 at 5 K, which is an order of magnitude higher than the best reported performance thus far. Importantly, the electro‐optic coefficient increases by 100 × during cooling, unlike the conventional films, where it degrades. Further, at the lowest temperature, significant higher order electro‐optic responses also emerge. These results represent a new framework for designing materials with property enhancements by stabilizing highly tunable metastable phases with strain. Dataset includes files used in figure preparation. Raw experimental data is available at reasonable request to the authors.摘要：针对可在低温条件下维持优异性能的薄膜电光材料的探索，已成为量子计算领域的关键研究方向。钛酸钡（Barium titanate）薄膜在室温下的四方相（tetragonal phase）中展现出较大的线性电光系数，但在低温菱方相（rhombohedral phase）中该系数会严重衰减至约200 pm·V⁻¹。学界对调控此类相变、并在液氦温度下仍保留优异电光性能有着极高的研究热情。本研究借助光学性质的热力学理论，通过调控不同铁电相（ferroelectric phases）间的能量竞争关系，设计出具备强低温电光响应的材料体系，最终获得了具有巨大电光响应的低对称性单斜相（monoclinic phase）。该相的存在已在应变调控钛酸钡薄膜中得到证实：该薄膜在5 K下的线性电光系数可达2516 ± 100 pm·V⁻¹，较目前已报道的最优性能高出一个数量级。值得注意的是，与传统薄膜在降温过程中电光系数衰减的特性不同，本研究中的薄膜其电光系数在降温过程中提升了100倍。此外，在最低测试温度下，还出现了显著的高阶电光响应。上述研究结果为通过应变稳定高度可调的亚稳相（metastable phases）以实现材料性能增强，提供了全新的设计框架。 本数据集包含用于绘制图表的相关文件。原始实验数据可通过合理申请向作者获取。