High-Entropy Alloy Superconductors under High Pressures

高压下的高熵合金超导体

• 批准号: 2310526
• 负责人: Yogesh Vohra
• 金额: $ 45.68万
• 依托单位: University of Alabama at Birmingham
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310526&HistoricalAwards=false
• 关键词: Entropy; Alloy; Superconductors; under; Pressures

PART 1: NON-TECHNICAL SUMMARYSuperconductors play a vital role in various sectors of the US economy ranging from energy transmission, medical imaging, magnetically confined plasma for fusion energy generation, high-speed transportation, as well as quantum computing and information technology. Superconducting materials are special because they exhibit zero resistance to current flow and spontaneously expel magnetic fields below a critical transition temperature. High-entropy alloys are a special class of metal that has near equal amounts of typically five or more elements as opposed to more conventional alloys that usually add small amounts of several elements to one base (e.g. Iron, Nickel, Cobalt). High-entropy alloys represent a new addition to the family of superconductors as they show a phenomenon of robust superconductivity, where the superconducting transition temperature is unaffected even when the material is subjected to very high pressure. This work is uncovering a fundamental understanding of the superconducting phenomenon in high-entropy alloys for the purposes of tailoring their microstructure using 3-D printing techniques to further enhance their ability to generate higher magnetic fields required for practical applications. This project supports graduate and undergraduate students who are receiving training at national experimental and computational facilities, leading to a pipeline of well-rounded materials science graduates for employment in academia, national laboratories, and industry. The University of Alabama at Birmingham in partnership with the Historically Black Colleges and Universities in the southeastern region jointly undertake efforts in broadening participation of underrepresented groups in the science and engineering fields.PART 2: TECHNICAL SUMMARYIn this project, combined theoretical and experimental expertise is called upon to investigate the phenomenon of robust superconductivity in high-entropy alloys at high-pressures and low-temperatures. Four-probe electrical resistance and magnetic susceptibility measurements on three classes of high-entropy alloy superconductors crystallizing in body-centered cubic phase (TiZrHfTaNb), hexagonal close-packed phase (TiZrHfReNb), and Cesium-Chloride type phase (RhPdScZrNb) are being conducted. The superconducting measurements are being extended to low temperatures of 1.9 K and pressures as high as 200 GPa using a custom diamond anvil with embedded probes for electrical transport and magnetic susceptibility measurements. The crystal structures of high-entropy alloy superconductors under high-pressures and low temperatures are also being examined using a synchrotron x-ray source. This study is providing corresponding first-principles calculations based on density functional theory, electron-phonon calculations, and stochastic random structures across three classes of high-entropy alloys as a function of external pressure. The resulting simulations of structural, electronic, and superconducting properties are being compared directly with experiments, which are helping benchmark the computational frameworks. Current studies on 3-D printed high-entropy alloy superconductors are offering unique microstructural control that increases the upper critical magnetic field which is of importance for practical applications of superconductors.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.

第一部分： 超导体在美国经济的各个领域都发挥着至关重要的作用，包括能源传输、医学成像、用于聚变能发电的磁约束等离子体、高速运输以及量子计算和信息技术。超导材料是特殊的，因为它们对电流流动表现出零电阻，并且在临界转变温度以下自发地排出磁场。高熵合金是一类特殊的金属，通常含有几乎等量的五种或更多种元素，而传统的合金通常在一种基础上添加少量的几种元素（例如铁，镍，钴）。高熵合金代表了超导体家族的新成员，因为它们表现出强大的超导性现象，即使材料受到非常高的压力，超导转变温度也不受影响。这项工作揭示了对高熵合金中超导现象的基本理解，目的是使用3D打印技术定制其微观结构，以进一步增强其产生实际应用所需的更高磁场的能力。该项目支持在国家实验和计算设施接受培训的研究生和本科生，为学术界、国家实验室和工业界提供全面的材料科学毕业生就业渠道。伯明翰的亚拉巴马大学与东南部地区历史上的黑人学院和大学合作，共同努力扩大科学和工程领域代表性不足的群体的参与。 技术总结在这个项目中，结合理论和实验的专业知识被要求在高压和低温下研究高熵合金中强大的超导现象。采用四探针法测量了体心立方相（TiZrHfTaNb）、六方密排相（TiZrHfReNb）和氯化铯型相（RhPdScZrNb）中三类高熵合金超导体的电阻和磁化率。超导测量正在扩展到1.9 K的低温和高达200 GPa的压力，使用定制的金刚石砧与嵌入式探针进行电传输和磁化率测量。高熵合金超导体在高压和低温下的晶体结构也正在使用同步加速器X射线源进行检查。这项研究提供了相应的第一性原理计算的基础上密度泛函理论，电子-声子计算，和随机随机结构在三类高熵合金作为外部压力的函数。由此产生的结构，电子和超导特性的模拟直接与实验进行比较，这有助于基准计算框架。目前对3D打印高熵合金超导体的研究提供了独特的微结构控制，增加了对超导体实际应用至关重要的上临界磁场。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。