New Approaches to Strain Engineering and Superconductivity

摘要：超导性是基础研究和实际应用中最重要的材料性质之一，研究超导性的新实验方法具有重要意义。在最近的突破性成果的基础上，这项工作的重点是使用创新的实验方法来扩大对超导性的理解。目前正在研究的两种主要方法是：利用沿多个方向施加的应力将调谐和工程特性结合起来，以及研究导致材料永久变形的应力效应。这两种方法都有巨大的未开发潜力，几乎没有被探索过。这项工作为研究与变形有关的缺陷对某些量子材料超导和正常状态特性的影响提供了令人兴奋和及时的机会。此外，该团队正在测试最近对半导体中应力诱导金属化和超导性的预测。这项研究为许多本科生和研究生提供了丰富的教育和研究机会，他们在美国国家实验室获得了晶体生长和表征、输运和热力学测量、中子和同步加速器x射线散射以及创新应变细胞和测量技术的使用方面的宝贵经验。技术摘要：基于最近新型高力气动应变单元的成功，显著改变和增强了大块氧化物的理想性能，本项目开始探索材料物理学中广阔的参数空间，重点研究塑性变形或受多轴应力作用的非氧化物材料的超导性能。目前正在采用两种主要方法：沿多个空间方向的应力组合，包括剪切应力；而应力的影响超过弹性极限，导致材料的永久、塑性变形。研究包括晶体生长和表征、输运和热力学测量、中子和同步加速器x射线散射，以及与互补光谱探针专家的合作。它侧重于三个精选材料家族：碲化物超导体，包括SnTe和PbTe；超导半赫斯勒化合物，最重要的是YPtBi；和传统的半导体，如硅和锗。总的来说，前两组涉及狄拉克和拓扑半金属，此外，碲化物由于其突出的热电性质而具有技术相关性。在传统半导体领域，该团队正在测试最近对剪切诱导金属化和超导性的预测。应用于这些材料的新方法有望超越超导领域，对未来量子材料的研究具有不可估量的价值。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Abstract:Superconductivity is among the most important materials properties for both fundamental research and practical applications, and the development of novel experimental approaches to superconductivity is of great interest. Building on recent break-through results, this work focuses on using innovative experimental methods to expand the boundaries of understanding superconductivity. Two main approaches are being pursued: the combination of tuning and engineering the properties using stress applied along multiple directions, and investigation of the effects of stress leading to permanent deformation of the material. Both approaches have great untapped potential and are virtually unexplored. The work provides the exciting and timely opportunity to investigate the influence of defects related to deformation on both superconducting and normal-state properties in certain quantum materials. Furthermore, the team is testing a recent prediction of stress-induced metallization and superconductivity in semiconductors. This research provides rich educational and research opportunities for a number of undergraduate and graduate students who are gaining valuable experiences in crystal growth and characterization, transport and thermodynamic measurements, neutron and synchrotron x-ray scattering at US national laboratories, and in the use of innovative strain cells and measurement techniques.Technical Abstract:Building on the recent success with novel high-force pneumatic strain cells to significantly modify and enhance desirable properties of bulk oxides, this project begins to explore a vast parameter space in materials physics, with focus on the superconducting properties of select non-oxide materials that are either plastically deformed or subjected to multiaxis stress. Two main approaches are being pursued: the combination of stress along multiple spatial directions, including shear stress; and the effects of stress that exceeds the elastic limit and leads to permanent, plastic deformation of the material. The research involves crystal growth and characterization, transport and thermodynamic measurements, neutron and synchrotron x-ray scattering, and collaboration with experts in complementary spectroscopic probes. It focuses on three select materials families: telluride superconductors, including SnTe and PbTe; superconducting half-Heusler compounds, most importantly YPtBi; and conventional semiconductors, such as Si and Ge. Broadly, the first two groups involve Dirac and topological semimetals and, moreover, tellurides are of technological relevance due to their outstanding thermoelectric properties. In conventional semiconductors, the team is testing a recent prediction of shear-induced metallization and superconductivity. The novel approaches applied to these materials can be expected to transcend the field of superconductivity and become invaluable to future studies of quantum materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.