Control of the Mott transition by uniaxial pressure

已知施加压力可从绝缘体诱导出金属态或提高超导体的转变温度。在这个项目中，我们专注于单轴压力的应用，以放大绝缘体-金属转变和奇异超导性的效果或提取基础机制。本文对脆性氧化物晶体低温实验的压力装置进行了改进，并介绍了一种既能施加压应变又能施加拉应变的新装置。使用层状钌氧化物，我们发现了一个强大的面内各向异性的过渡，从莫特绝缘体的铁磁金属。我们还发现，氧化钌Sr 2 RuO 4的超导转变是增强的压缩和拉伸应变，从而证实了预期的不寻常的行为在自旋三重态超导体与对齐的铜对角动量。这些结果证明了单轴压力实验的有用性。

Application of pressure is known to induce a metallic state from an insulator or to enhance the transition temperature of a superconductor. In this project, we focus on the application of uniaxial pressure in order to amplify the effect or extract underlining mechanisms of an insulator-metal transition and exotic superconductivity. We improve the pressure apparatus for low-temperature experiments on brittle oxide crystals, as well as introduce a new apparatus capable of application of both compressional and tensile strain. Using layered ruthenium oxides, we found a strong in-plane anisotropy of the transition from a Mott insulator to a ferromagnetic metal. We also found that the superconducting transition of the ruthenium oxide Sr2RuO4 is enhanced by both compressional and tensile strain, thereby confirming the unusual behavior expected in a spin-triplet superconductor with aligned Cooper-pair angular momenta. These results demonstrate the usefulness of uniaxial pressure experiments.