Thermoelectric Effects in Superconductor-Ferromagnet Hybrids

超导体-铁磁体混合体中的热电效应

• 批准号: 1807583
• 负责人: Meenakshi Singh
• 金额: $ 45.3万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1807583&HistoricalAwards=false
• 关键词: Thermoelectric; Effects; Superconductor; Ferromagnet; Hybrids

Non-technical abstract: Thermoelectric systems convert heat to electricity and vice versa. They have applications in refrigeration, waste heat recovery, and thermometry. With no gas or liquid components and no moving parts, thermoelectric devices are small, portable, and sturdy. However, the energy conversion efficiency of thermoelectric materials decreases with decreasing temperature. Therefore, to date, there is no efficient thermoelectric systems operating below ~ 200 K. The thermoelectric system this project is focused on fabricating and measuring, is predicted to be efficient at elevated temperatures. From a technology perspective, this will enable applications that were previously thought impossible such as thermoelectric cooling for cryogenic devices and space telescopes. This project trains a new generation of students with expertise in quantum systems, synthesis, characterization, cryogenics, low-noise electronics, and computation. Undergraduate research and recruitment of underrepresented groups is facilitated through Colorado School of Mines' bridge program with community colleges. Additionally, modules are being developed, introducing the science behind this project, for use in Mines' outreach programs to Denver Public Schools, Vertical Skills Academy (which is a school for dyslexic children in Evergreen, CO), and the community.Technical abstract: Thermoelectric effects, which are normally negligible in superconductors, are expected to increase dramatically in superconductor (S) - ferromagnet (F) hybrids. Although exciting theoretical predictions abound, there are hardly any experimental studies in this field. Moreover, there are no studies, experimental or theoretical, on the role of dimensionality and the nature of superconductivity (singlet vs. triplet). This is a tremendous missed opportunity for several reasons. First, if the predictions of high thermoelectric figure of merit at cryogenic temperatures are correct, S-F systems will be the only efficient thermoelectrics in this temperature range. Second, there is fascinating Physics at S-F interfaces, including triplet superconductivity, seen in charge and spin transport measurements. Thermoelectric effects offer a novel probe into this Physics. Third, the effects of reduced dimensionality on quasiparticles in a superconductor, which are relevant for thermal effects, has not been explored. Finally, there are a number of fascinating predictions for thermal effects in S-F systems that have not been realized because the 'groundwork' experiments are missing. This project fills this gap by systematically investigating thermoelectric effects in S-F hybrids using low-temperature, charge, spin and thermal transport measurements. The results test existing theoretical predictions, inform future studies and explore heralded applications including nanoscale cooling. These efforts build upon the PI's expertise in nanoscale fabrication and low temperature transport experiments.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.

非技术摘要：热电系统将热量转换为电力，反之亦然。他们在制冷，废热回收和温度计中有应用。没有气体或液体组件，也没有运动部件，热电设备小，便携式和坚固。但是，热电材料的能量转化效率随温度降低而降低。因此，迄今为止，在〜200 k以下运行的热电系统还没有有效的热电系统。热电系统该项目专注于制造和测量，预计在升高温度下将有效。从技术的角度来看，这将使以前认为不可能的应用程序，例如低温设备和太空望远镜的热电冷却。该项目训练新一代学生在量子系统，合成，表征，低温，低噪声电子和计算方面具有专业知识。科罗拉多州矿业学院的桥梁计划与社区学院促进了代表性不足的群体的本科研究和招聘。此外，正在开发模块，引入该项目背后的科学，用于矿山的外展计划，用于丹佛公立学校，垂直技能学术学院（这是一所垂直技能学院（这是一所在CO，CO，CO）和社区的社区。技术摘要：热电学效果，这些效果通常会在超级范围内增加，而在超级方面可以忽略不计，这些效果是超级conc的（fer）。杂种。尽管令人兴奋的理论预测比比皆是，但在该领域几乎没有任何实验研究。此外，没有关于维度和超导性质的作用的实验性或理论研究（Singlet vs. Triplet）。由于几个原因，这是一个巨大的错过机会。首先，如果在低温温度下对高热电学值的预测是正确的，则S-F系统将是该温度范围内唯一有效的热电学。其次，在S-F界面上有引人入胜的物理学，包括电荷和自旋传输测量值的三联超导性。热电效应为该物理学提供了一种新颖的探测。第三，尚未探索与热效应相关的超导体中准颗粒的影响。最后，由于缺少“基础”实验，因此对于S-F系统中的热效应有许多令人着迷的预测。该项目通过使用低温，电荷，自旋和热运输测量结果系统地研究S-F杂种中的热电效应来填补这一空白。结果测试了现有的理论预测，为未来的研究提供了信息，并探索了包括纳米级冷却在内的预示应用。这些努力基于PI在纳米级制造和低温运输实验方面的专业知识。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来支持的。

项目成果

Focused ion beam deposited carbon-platinum nanowires for cryogenic resistive thermometry

• DOI: 10.1016/j.carbon.2020.06.087
• 发表时间: 2020-11-01
• 期刊: CARBON
• 影响因子: 10.9
• 作者: Blagg, Kirsten;Allen, Portia;Singh, Meenakshi
• 通讯作者: Singh, Meenakshi

Template-based electrodeposition and characterization of niobium nanowires

铌纳米线的基于模板的电沉积和表征

• DOI: 10.1016/j.elecom.2019.02.011
• 发表时间: 2019
• 期刊: Electrochemistry Communications
• 影响因子: 5.4
• 作者: Blagg, Kirsten;Greymountain, Tamara;Kern, Wolfgang;Singh, Meenakshi
• 通讯作者: Singh, Meenakshi

On-chip heating effects in electronic measurements at cryogenic temperatures

低温电子测量中的片上热效应

• DOI: 10.1016/j.cryogenics.2022.103536
• 发表时间: 2022
• 期刊: Cryogenics
• 影响因子: 2.1
• 作者: Blagg, Kirsten;Castagnède, Antoine;Singh, Meenakshi
• 通讯作者: Singh, Meenakshi