Tuning electronic instabilities in triangular surface lattices via subsurface doping

非技术摘要：该项目旨在通过化学掺杂实验可控地改变单原子薄膜材料的电子特性。 所研究的薄膜系统由锡或铊原子以各种三角形图案排列在硅衬底上组成。 单原子锡层是特别感兴趣的，因为有可能获得新的电子材料与可能的异国情调的性质，如通过化学掺杂的超导性。 通过对单原子铊薄膜进行化学掺杂可以获得奇异磁性。 为了推进一类新的电子材料作为硅的可能替代品，例如，用于信息技术的纳米电子器件。 田纳西大学拟议的科学和支持基础设施为具有国际竞争力的研究生的教育和培训提供了良好的环境。 一项将赞助研究与本科教育相结合的严格计划正在实施，以提高物理专业的入学率。 该推广计划的目标是大二和初中学生谁是参加著名的田纳西州州长学校的科学和工程。 通过为所有这些年轻人提供独特的研究和教育经验，研究人员的目标是吸引这些深刻的思想家和未来的决策者追求物理科学的高级学位。技术摘要：推进复杂材料的知识和实际应用的一个关键方面是通过化学掺杂控制其电子特性的能力。 对于严格的二维系统，化学掺杂不可避免地引入结构无序，因为电离的掺杂剂杂质成为二维电子系统的组成部分。 该项目建立在早期NSF赞助的研究的主要成就，其中表面层或薄膜的空穴掺杂是通过亚表面或？调制掺杂？ 与复杂氧化物系统的研究类似，研究旨在拓宽空穴掺杂剂的浓度范围，并将调制掺杂概念扩展到n型物种，从而建立完整的电子相图。 这种策略被用来掺杂三角形表面晶格与强莫特相关性和强自旋轨道耦合。 激发的可能性d-波超导性在前者，和自旋密度波不稳定性在后者将被探索作为掺杂水平的函数。 该项目涉及在真空中的薄膜生长，扫描隧道显微镜和光谱学，以及角度分辨光电发射实验，所有这些都与外部合作者的理论支持相结合。田纳西大学拟议的科学和支持基础设施为具有国际竞争力的研究生的教育和培训提供了良好的环境。 一项将赞助研究与本科教育相结合的严格计划正在实施，以提高物理专业的入学率。 该推广计划的目标是大二和初中学生谁是参加著名的田纳西州州长学校的科学和工程。 通过为所有这些年轻人提供独特的研究和教育经验，研究人员的目标是吸引这些深刻的思想家和未来的决策者追求物理科学的高级学位。

Non-Technical Abstract:This project aims to controllably modify the electronic properties of monatomic thin film materials via chemical doping experiments. The thin film systems under investigation consist of tin or thallium atoms arranged in various triangular patterns on a silicon substrate. The monatomic tin layer is of particular interest because there is the potential to obtain novel electronic materials with possibly exotic properties, such as superconductivity via chemical doping. Exotic magnetism may be obtained through the chemical doping of monatomic thallium films. Atomic-scale understanding of the quantum mechanical mechanisms that give rise to such emergent electronic behavior is crucial in order to advance a new class of electronic materials as the possible replacement of silicon in, e.g., nano-electronic devices used in information technology. The proposed science and supporting infrastructure at The University of Tennessee provide an excellent setting for the education and training of internationally competitive graduate students. A rigorous plan for integrating sponsored research with undergraduate education is being implemented to boost enrolment in the physics major. The outreach program targets sophomore and junior high school students who are participating in the prestigious Tennessee Governor School for the Sciences and Engineering. By providing all of these young people with unique research and educational experiences, the investigators aim to entice these deep thinkers and future decision-makers to pursue an advanced degree in the physical sciences. Technical Abstract:A critical aspect for advancing knowledge and practical applications of complex materials is the ability to control their electronic properties via chemical doping. For a strictly two-dimensional system, chemical doping inevitably introduces structural disorder as the ionized dopant impurities become an integral part of the two-dimensional electron system. This project builds on the main accomplishments from earlier NSF sponsored research, in which hole doping of a surface layer or thin film was accomplished via subsurface- or ?modulation doping?. In analogy with studies on complex oxide systems, the investigations aim to widen the concentration range of the hole dopants and expand the modulation doping concept to n-type species, so as to establish a full electronic phase diagram. This strategy is being employed to dope triangular surface lattices with strong Mott correlations and strong spin-orbit coupling. The exciting possibilities of d-wave superconductivity in the former, and spin density wave instabilities in the latter will be explored as a function of the doping level. The project involves thin film growth in ultrahigh vacuum, scanning tunneling microscopy and spectroscopy, and angle-resolved photoemission experiments, all in conjunction with theoretical support from outside collaborators. The proposed science and supporting infrastructure at The University of Tennessee provide an excellent setting for the education and training of internationally competitive graduate students. A rigorous plan for integrating sponsored research with undergraduate education is being implemented to boost enrolment in the physics major. The outreach program targets sophomore and junior high school students who are participating in the prestigious Tennessee Governor School for the Sciences and Engineering. By providing all of these young people with unique research and educational experiences, the investigators aim to entice these deep thinkers and future decision-makers to pursue an advanced degree in the physical sciences.