EAPSI: Thickness Dependence of the Magnetic Properties of the Ferromagnetic Insulator Cr2Ge2Te6

EAPSI：铁磁绝缘体 Cr2Ge2Te6 磁性的厚度依赖性

• 批准号: 1614103
• 负责人: Jacob Hudis
• 金额: $ 0.54万
• 依托单位: Hudis Jacob B
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1614103&HistoricalAwards=false
• 关键词: EAPSI; Thickness; Dependence; Magnetic; Properties

The research and education activities supported by this award focus on studying the evolution of magnetism as a function of thickness in Cr2Ge2Te6, a type of material known as a ferromagnetic insulator (FMI). Cr2Ge2Te6 is interesting in condensed matter physics because it is one of only a small number of materials that is both ferromagnetic and an insulator. The first part of the project will take crystals of Cr2Ge2Te6, , and exfoliate them down until we have a set of samples with varying thicknesses of a few unit cells. Next, the magnetic properties of the samples will be studied using a technique known as micro-Hall magnetrometry. By studying the magnetic properties of the samples, one can obtain information about how the strength of the permanent magnet evolves with thickness. If time permits, small flakes of Cr2Ge2Te6 will be combined in a sandwich with another material, a topological insulator, of similar crystal structure. Measuring the properties of the sandwich structure can provide information about how the electrons behave at the interface of the two materials. Such an interface between a ferromagnetic insulator and a topological insulator may host novel physical phenomena such as the quantum anomalous Hall effect. This project will be conducted under the mentorship of Professor Yongqing Li at the Institute of Physics, Chinese Academy of Sciences.This projects involves a study of the magnetic properties of ultrathin layers of the ferromagnetic insulator (FMI) Cr2Ge2Te6. Professor Yongqing Li at the Institute of Physics has obtained high quality single crystals of this material, which is a layered ferromagnetic insulator that can be exfoliated down to few atomic layers in thickness. One near term goal is to study the evolution of the magnetism as a function of thickness. Because of the small volumes of the ultrathin specimens, the magnetic properties will be measured with micro-Hall magnetometry and surface-sensitive micro-Kerr microscopy. After gaining good understanding of the magnetic properties of the FMI, the team will explore integrating the exfoliated ultrathin Cr2Ge2Te6 onto a topological insulator (TI). The PI will also perform initial magnetotransport measurements on the hybrid FMI/TI structure. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of China.

该奖项支持的研究和教育活动重点研究 Cr2Ge2Te6 中磁性随厚度变化的演变，Cr2Ge2Te6 是一种被称为铁磁绝缘体 (FMI) 的材料。 Cr2Ge2Te6 在凝聚态物理中很有趣，因为它是少数既具有铁磁性又具有绝缘体的材料之一。该项目的第一部分将采用 Cr2Ge2Te6 晶体，并将它们剥落下来，直到我们得到一组具有不同厚度的几个晶胞的样品。 接下来，将使用称为微霍尔磁力测量的技术来研究样品的磁性。 通过研究样品的磁性，可以获得有关永磁体的强度如何随厚度变化的信息。 如果时间允许，Cr2Ge2Te6 的小薄片将与另一种材料（具有相似晶体结构的拓扑绝缘体）组合在三明治中。 测量夹层结构的特性可以提供有关电子在两种材料界面处行为方式的信息。 铁磁绝缘体和拓扑绝缘体之间的这种界面可能会产生新的物理现象，例如量子反常霍尔效应。该项目将在中国科学院物理研究所李永清教授的指导下进行。该项目涉及铁磁绝缘体（FMI）Cr2Ge2Te6超薄层的磁性能研究。 物理研究所李永清教授获得了这种材料的高质量单晶，它是一种层状铁磁绝缘体，可以剥离至几个原子层的厚度。近期目标之一是研究磁性随厚度的变化。由于超薄样品体积小，因此将使用微霍尔磁力计和表面敏感微克尔显微镜来测量磁性。 在充分了解 FMI 的磁性后，该团队将探索将剥离的超薄 Cr2Ge2Te6 集成到拓扑绝缘体 (TI) 上。 PI 还将对混合 FMI/TI 结构进行初始磁输运测量。 该奖项属于东亚和太平洋地区暑期学院项目，支持美国研究生的暑期研究，由美国国家科学基金会和中国科学技术部共同资助。