RUI: Collaborative Research: Spin-gapless semiconductivity and half-metallicity in Heusler alloys

RUI：合作研究：霍斯勒合金中的自旋无隙半导体性和半金属性

• 批准号: 2003828
• 负责人: Pavel Lukashev
• 金额: $ 23.63万
• 依托单位: University of Northern Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003828&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Spin; gapless

Non-Technical Abstract:Current computing technology is based on the manipulation of the charge of electrons for the purpose of information processing. Hard disks, which are used in large-scale storage of data, function by exploiting the intrinsic magnetism of electrons. Spintronics is a fledging field that unites these two technologies to create a new computing paradigm that could result in substantial enhancements in computing speed and attendant energy efficiency. Spintronic devices such as magnetic random access memory (MRAM) have already been commercialized but the potential of spintronics is far greater. This project advances the field of spintronics through the systematic discovery of new materials that possess the necessary electronic and magnetic properties to undergird large-scale development of new spintronic devices. The project combines both theoretical and experimental approaches to maximize the effectiveness of the discovery process. In addition to its direct scientific impact, the project positively influences the development of the future science and technology workforce through the heavy involvement of undergraduate students in all aspects of the research. Outreach programs involving K-12 students and the general public further broadens the impact of the project via engaging activities that emphasize and elevate the importance of science to the well-being of humanity. This project is jointly funded by the Division of Materials Research (DMR) and the Established Program to Stimulate Competitive Research (EPSCoR).Technical Abstract:The main goal of this project is the identification and synthesis of new half-metallic (HM) and spin-gapless semiconducting (SGS) materials for applications in spintronics. In particular, this project investigates structural, magnetic, electronic, and spin-transport properties of HM and SGS Heusler alloys in bulk and thin-film geometry. This is achieved by performing comprehensive theoretical and experimental investigations of candidate materials, using state-of-the-art techniques, tools, and research methods, including X-ray diffraction, transmission electron microscopy, Quantum Design VersaLab magnetometer, Quantum Design Physical Property Measurement System, point-contact Andreev reflection, and first-principles density functional calculations. The project is motivated by recent discovery that certain Heusler compounds change their ground state from metallic to SGS and/or HM upon modification of their elemental compositions. This approach has a clear advantage over mechanical strain-induced half-metallic transitions reported in the literature, as it requires no external pressure. Second, this project provides experimental confirmation that certain half-metals retain a 100% spin-polarization in thin-film geometry, contrary to the conventional wisdom that reduced geometry destroys half-metallicity due to the emergence of surface states. This could open a new page in spintronic applications, e.g., in devices based on multilayer design, such as magnetoresistive tunnel junctions. This project is jointly funded by the Division of Materials Research (DMR) and the Established Program to Stimulate Competitive Research (EPSCoR).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：目前的计算技术是基于对电子电荷的操纵来进行信息处理。硬盘用于大规模数据存储，其功能是利用电子的本征磁性。自旋电子学是一个羽翼未丰的领域，它将这两种技术结合起来，创造出一种新的计算模式，可能会在计算速度和随之而来的能源效率方面产生实质性的增强。磁随机存取存储器(MRAM)等自旋电子器件已经商业化，但自旋电子学的潜力要大得多。该项目通过系统地发现具有必要的电磁特性的新材料来推动自旋电子学领域的发展，以支持新的自旋电子器件的大规模开发。该项目结合了理论和实验方法，以最大限度地提高发现过程的有效性。除了直接的科学影响外，该项目还通过本科生对研究的各个方面的大量参与，对未来科学技术劳动力的发展产生了积极影响。涉及K-12学生和普通公众的外联计划通过开展强调和提升科学对人类福祉的重要性的活动，进一步扩大了该项目的影响。该项目由材料研究部(DMR)和已建立的促进竞争研究计划(EPSCoR)共同资助。技术摘要：该项目的主要目标是识别和合成用于自旋电子学应用的新型半金属(HM)和自旋无隙半导体(SGS)材料。特别是，本项目研究了HM和SGS Heusler合金的块体和薄膜几何结构、磁、电子和自旋输运性质。这是通过对候选材料进行全面的理论和实验研究，使用最先进的技术、工具和研究方法实现的，包括X射线衍射、透射电子显微镜、量子设计VersaLab磁强计、量子设计物理性能测量系统、点接触安德列夫反射和第一原理密度泛函计算。该项目的动机是最近发现，某些Heusler化合物在改变其元素组成后，其基态从金属转变为SGS和/或HM。与文献中报道的机械应变诱导的半金属转变相比，这种方法具有明显的优势，因为它不需要外部压力。其次，这个项目提供了实验证实，某些半金属在薄膜几何结构中保留了100%的自旋极化，而不是传统的观点，即减少的几何结构由于表面态的出现而破坏了半金属的丰度。这可以在自旋电子学的应用中打开新的一页，例如在基于多层设计的设备中，例如磁阻隧道结。该项目由材料研究部(DMR)和既定的激励竞争性研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Structural, electronic, and magnetic properties of CoFeVGe-based compounds: Experiment and theory

CoFeVGe 基化合物的结构、电子和磁性特性：实验和理论

• DOI: 10.1063/9.0000395
• 发表时间: 2023
• 期刊: AIP Advances
• 影响因子: 1.6
• 作者: Kharel, Parashu;Lehmann, Zachary;Baker, Gavin;Stuelke, Lukas;Valloppilly, Shah;Shand, Paul M.;Lukashev, Pavel V.
• 通讯作者: Lukashev, Pavel V.

Electronic, structural and magnetic properties of Mn(1+x)Pt(1-x)Sb

Mn(1 x)Pt(1-x)Sb 的电子、结构和磁性

• DOI: 10.1016/j.jmmm.2021.168234
• 发表时间: 2021
• 期刊: Journal of Magnetism and Magnetic Materials
• 影响因子: 2.7
• 作者: Al Maruf, Abdullah;Ramker, Adam;Valloppilly, Shah;Shand, Paul M.;Lukashev, Pavel V.;Kharel, Parashu
• 通讯作者: Kharel, Parashu

Effect of atomic disorder on electronic, magnetic and electron-transport properties of Ti2MnAl

• DOI: 10.1016/j.jallcom.2021.162625
• 发表时间: 2021-11
• 期刊: Journal of Alloys and Compounds
• 影响因子: 6.2
• 作者: P. Lukashev;Zachary Lehmann;L. Stuelke;R. Filippone;Bishnu R. Dahal;S. Valloppilly;J. Waybright;A. Pathak;Y. Huh;P. Shand;P. Kharel

Experimental and theoretical investigation of FeCrVAl and related compounds

FeCrVAl 及相关化合物的实验和理论研究

• DOI: 10.1088/1402-4896/aca446
• 发表时间: 2022
• 期刊: Physica Scripta
• 影响因子: 2.9
• 作者: Lukashev, Pavel V;Stuelke, Lukas;Pottebaum, Zach;Moua, Young;Baker, Gavin;Wysong, Jax;Flesche, Matthew;Valloppilly, Shah;Shand, Paul M;Kharel, Parashu
• 通讯作者: Kharel, Parashu

Synthesis, crystal structure, and magnetic properties of CoMoFeAl and related compounds

CoMoFeAl及相关化合物的合成、晶体结构和磁性能

• DOI: 10.1063/9.0000396
• 发表时间: 2023
• 期刊: AIP Advances
• 影响因子: 1.6
• 作者: Baker, Gavin;Wysong, Jax;Valloppilly, Shah;Shand, Paul;Lukashev, Pavel;Kharel, Parashu
• 通讯作者: Kharel, Parashu