Elasto-superconductivity: a pathway to devising new unconventional superconductors

超导性是指在足够低的温度下，某些材料的电阻率降至零。它被广泛用于高功率应用和极端磁场--例如，医疗保健中的磁共振/核磁共振机、高输出风力涡轮机和磁悬浮高速列车。全球超导体市场目前估计超过5.5亿GB，预计到下一个十年将翻一番。超导性是量子力学在大长度尺度上的显著表现，它支撑了一些最令人兴奋的技术可能性。其中之一是新兴的量子计算领域，其中最有希望的原型是基于固态超导芯片的。然而，超导性是一种微妙的状态：它需要较低的温度，并对周围磁场进行限制。许多已知的具有强大超导电性的材料都有很难的机械性能。因此，超导材料有巨大的优化空间，带来巨大的技术和经济利益。最有希望成为更实用的高温超导体的候选材料是所谓的“非常规”超导体，在这种超导体中，许多电子之间强烈而复杂的相互作用会导致特别强劲的超导电性。它们最终可能提供一条通向室温超导的途径。然而，我们控制高温超导电性的能力仍然严重受限。其中一个主要挑战是复杂性：电子之间的强烈相互作用通常会导致它们以其他方式有序，例如形成被称为电荷密度波的带状电荷。在强相互作用电子可能形成的许多结构中，尚不清楚哪些结构与超导性有关。在这个项目中，我们通过对材料进行实验来分离非传统超导电性的关键方面，以及旨在以保证精度的方式预测复杂相关系统的性质的计算来解决这个问题。我们利用最近关联电子系统的精确数值方法的巨大进步，以制定实现所需性质的具体条件。这些计算将通过这一提议的实验部分的结果来验证，并反过来将产生可在实验中验证的假设。这里采用的实验方法是对样品施加极大的压力，以使其晶格扭曲。这种方法被证明是非常强大的：在高压下，许多材料的电子性质与未加压的材料有如此大的不同，以至于它们实际上可以被视为新材料。我们的结果将提供对有利于增强超导电性的关键条件的洞察，并允许开发用于可再生能源和量子计算等应用的改进材料。

Superconductivity is a decrease of the electrical resistivity to zero, in certain materials and at sufficiently low temperature. It is widely employed for high-power applications and extreme magnetic fields - for example, in MRI/NMR machines in healthcare, in high-output wind turbines, and in magnetically-levitated high-speed trains. The global superconductor market is currently estimated at over £5.5B, and is expected to double by the next decade. Superconductivity is a remarkable manifestation of quantum mechanics on large length scales, and underpins some of the most exciting technological possibilities. One of them is the emerging field of quantum computation, in which the most promising prototypes are based on solid-state superconducting chips. However, superconductivity is a delicate state: it requires low temperatures, and limits on the ambient magnetic field. Many known materials with robust superconductivity have difficult mechanical properties. There is therefore enormous scope for optimisation of superconducting materials, with huge technological and economic benefits. The most promising candidates for a more practical high-temperature superconductor are the so-called "unconventional" superconductors, in which strong and complex correlations between many electrons induce particularly robust superconductivity. They may ultimately provide a route to room-temperature superconductivity. However, our ability to control high-temperature superconductivity has remained severely limited. One of the main challenges is complexity: the strong interactions among electrons often cause them to order in other ways, such as into ribbons of charge known as charge density waves. Of the many structures that strongly-interacting electrons can form, it is unclear which are related to the superconductivity.In this project, we take on this problem through a combination of experiments on materials that isolate key aspects of unconventional superconductivity, and calculations designed to predict properties of complex, correlated systems with guaranteed accuracy. We take advantage of the dramatic recent progress of precision numerical methods for correlated electron systems, in order to formulate specific conditions for achieving desired properties. These calculations will be validated by results from the experimental portion of this proposal, and in turn will generate hypotheses that are testable experimentally. The experimental method to be employed here is to apply extremely large pressures to samples, in order to distort their lattices. This method has proved to be very powerful: under high pressure, the electronic properties of many materials differ so much from the unpressurised material that they can be considered, in effect, as new materials. Our results will provide insight into the key conditions that favour robust superconductivity, and allow development of improved materials for applications such as in renewable energy and quantum computation.