ARPES Study of Electronic Evolution from Mott Insulators to Novel Superconductors

从莫特绝缘体到新型超导体的电子演化的 ARPES 研究

• 批准号: 0353108
• 负责人: Hong Ding
• 金额: $ 33万
• 依托单位: Boston College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-15 至 2007-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0353108&HistoricalAwards=false
• 关键词: ARPES; Study; Electronic; Evolution; Mott

This individual investigator award will support continued angle-resolved photoemission (ARPES) studies on the evolution of the electronic structure of novel superconductors. The materials studied in this project include superconducting cuprates, ruthenates, and cobaltates. All of them are 2D oxides that become superconducting when doped away from half-filled Mott insulator states. Unconventional superconductivity in these materials is one of the most important topics in condensed matter physics. In addition, other exotic phases, such as charge (spin) ordered states, may develop at certain doping. The physics of these states are of great importance as well. This project involves systematic ARPES studies on these materials over wide doping ranges. It will help us to understand the underlying electronic structure of the different phases. Besides the 'traditional' measurements of band dispersion and Fermi surface, many-body interactions, which are crucial in these strongly correlated materials, will be also investigated by high-resolution ARPES. A better understanding of the electronic structure in doped Mott insulators will significantly advance our knowledge of Mott physics, novel superconductivity, low dimensionality, quantum criticality, and non-Fermi liquid physics. This project will also make a significant impact on the education of high school students, undergraduate, graduate students, and post-docs by introducing them to exciting new materials, cutting-edge techniques, and fundamental condensed matter physics. Unlike traditional insulators that have either empty or completely filled outermost electron orbitals, the so-called "Mott" insulators have highest orbitals that are partially filled. Their insulating nature comes from strong interactions among the electrons. More interestingly, when extra electrons are added or removed from the Mott insulators, they exhibit many unusual physical phenomena. Some such "doped" materials show a very large change in their electrical resistance when placed in a magnetic field. Others become superconducting, lose all electrical resistance, above the temperature of liquid nitrogen - the so-called high temperature superconductors. Several doped Mott insulators, which exhibit novel superconductivity, are the focus of this experimental project. The technique of photoemission is used to knock out electrons from a solid sample through the absorption of ultraviolet light. The emitted electrons are studied to gain information about their configuration inside the solid, the electronic structure of the material. The electronic structure is crucial for the understanding of many of the materials' properties. The proposed systematic photoemission studies, over wide doping ranges, will help us understand the underlying electronic structure of many exotic phases in these materials. The success of this project will significantly advance our understanding of high temperature superconductivity and Mott physics in general. A better understanding of the physics of these novel materials will be helpful in realizing their application potentials. This project will also make a significant impact on the education of students by introducing them to exciting new materials, cutting-edge techniques, and advanced physics. They will gain the experience of participating in research at national facilities.

这一个人研究人员奖将支持对新型超导体电子结构演变的持续角度分辨光电子发射(ARPES)研究。本项目研究的材料包括超导铜酸盐、铬酸盐和钴酸盐。它们都是2D氧化物，当掺杂离开半填满的Mott绝缘态时，就会变成超导。这些材料中的非常规超导电性是凝聚态物理中最重要的课题之一。此外，在某些掺杂条件下，可能会出现其他奇异相，如电荷(自旋)有序态。这些态的物理学也是非常重要的。该项目涉及对这些材料进行广泛掺杂范围的系统ARPES研究。这将有助于我们理解不同相的潜在电子结构。除了对能带色散和费米表面的“传统”测量外，在这些强关联材料中至关重要的多体相互作用也将被高分辨率的ARPES研究。更好地理解掺杂Mott绝缘体中的电子结构将极大地促进我们对Mott物理、新型超导、低维、量子临界和非费米液体物理的了解。该项目还将通过向高中生、本科生、研究生和博士后介绍令人兴奋的新材料、尖端技术和基础凝聚态物理，对他们的教育产生重大影响。与最外层电子轨道空或完全填满的传统绝缘体不同，所谓的“莫特”绝缘体的最高轨道是部分填满的。它们的绝缘性来自于电子之间的强烈相互作用。更有趣的是，当额外的电子从Mott绝缘体中添加或移除时，它们会显示出许多不寻常的物理现象。一些这样的“掺杂”材料在置于磁场中时，其电阻会发生很大的变化。其他的则变成超导，失去所有的电阻，高于液氮的温度--即所谓的高温超导体。几种具有新型超导电性的掺杂Mott绝缘体是本实验项目的重点。光电子技术是利用紫外光吸收固体样品中的电子。对发射的电子进行研究，以获得关于它们在固体中的配置和材料的电子结构的信息。电子结构对于了解材料的许多性质至关重要。所提出的在宽掺杂范围内进行系统的光电子能谱研究，将有助于我们了解这些材料中许多奇异相的潜在电子结构。该项目的成功将极大地促进我们对高温超导和Mott物理的理解。深入了解这些新材料的物理性质将有助于实现它们的应用潜力。该项目还将通过向学生介绍令人兴奋的新材料、尖端技术和高级物理，对学生的教育产生重大影响。他们将获得在国家设施参与研究的经验。