CAREER: Interplay of Disorder and Quantum Effects in Low Dimensional Magnets and Superconductors

这是一项职业成就奖，授予在以本科生为主的院校工作的女科学家。本研究将探讨具有量子效应和无序性的磁性和超导系统的静态和动态特性。一个系统由随机的铁磁或反铁磁量子自旋链组成，可以用一个一维的S=1/2的海森堡哈密顿猝灭无序量来描述。第二个系统由有序和无序的二维伊辛反铁磁体组成，具有短程和远程相互作用。横向场中的二维伊辛系统是期望表现出量子相变的最简单的系统。第三种磁性系统由超导薄膜中的磁涡流组成，薄膜中含有有序和无序的孔阵列。无序系统可以用随机位置随机场Ising模型（RS/RFIM）来描述，其中粒子的相互作用强度通过简单地改变外加磁场来控制。自旋系统的关键性质将通过测量低温磁化率作为温度和磁场的函数来探测。超导体中涡旋的局部静态结构将使用Bitter装饰进行检测，而涡旋的局部动态运动将使用霍尔探针阵列进行测量。该职业奖的教育部分将支持一门名为“从微观到宏观：探索原子、分子和固体的性质”的本科研究课程的开发。本课程将着重于原子和凝聚态物理的实验技术，强调从原子到固体的电子和热性质的连续性，并借鉴卫斯理大学物理系的研究经验。这是一个职业奖，颁发给在以本科生为主的机构工作的女科学家。物理学家已经成功地对各种材料的电子和磁性有了详细的了解。然而，由于无序和强电子相互作用的存在，某些材料还没有产生这样的理解。对这些材料的深入了解将有助于开发这些材料的先进技术应用。本项目将重点研究三种磁性体系中无序和粒子间相互作用的作用。其中两个与电子自旋产生的磁性有关。第三种是磁通管系统，称为涡流，发生在具有故意制造缺陷的超导薄膜中。该基金还将支持本科生研究课程的发展，题为“从微观到宏观：探索原子、分子和固体的性质”。本课程将着重于原子和凝聚态物理的实验技术。它将强调从相对简单的原子到复杂固体的通用物理概念。这门课程将借鉴卫斯理大学物理系的研究经验。这门课程也将提供给参加卫斯理大学研究生通识课程暑期班的高中教师。本课程将为本科生和高中教师在学年或随后的夏季在研究实验室工作做好准备。＊＊＊

9733848 Beauchamp This is a CAREER award to a female scientist at a predominantly undergraduate institution. The research will explore the static and dynamic properties of magnetic and superconducting systems which exhibit quantum effects and disorder. One system consists of random ferromagnetic or antiferromagnet quantum spin chains which can be described by a one-dimensional, S=1/2 Heisenberg Hamiltonian with quenched disorder. The second system consists of ordered and disordered two-dimensional Ising antiferromagnets, with both short range and long range interactions. The two- dimensional Ising system in a transverse field is the simplest system which is expected to exhibit a quantum phase transition. The third magnetic system is consists of magnetic vortices in thin superconducting films containing ordered and disordered arrays of holes. The disordered system can be described by the random site, random field Ising model (RS/RFIM) in which particle interaction strength is controlled by simply changing the applied magnetic field. The critical properties of the spin systems will be probed via measurements of low temperature susceptibilities as a function of temperature and magnetic field. The local static configurations of the vortices in the superconductors will be examined using Bitter decoration, while the local dynamic motion of the vortices will be measured with Hall probe arrays. The educational component of this CAREER award will support development of an undergraduate research course, entitled "From the Minute to the Macroscopic: Probing the Properties of Atoms, Molecules, and Solids". The course will focus on experimental techniques in atomic and condensed matter physics, emphasizing the continuum in electronic and thermal properties from atoms to solids, and drawing on the research experience of the physics faculty at Wesleyan. %%% This is a CAREER award to a female scientist at a predominantly undergraduate institution. Physicists have been successful in developing a detailed understanding of electronic and magnetic properties in a wide range of materials. However, certain materials have not yielded to such an understanding owing to the presence of disorder and strong electronic interactions. A deeper understanding of such materials should aid in the development of advanced technological applications of these materials. This project will focus on the role of disorder and interparticle interactions in three magnetic systems. Two of these involve the magnetism produced by spins of electrons. The third is a system of magnetic flux tubes, called vortices, occurring in superconducting thin films with intentionally fabricated defects. The grant will also support the development of an undergraduate research course, entitled "From the Minute to the Macroscopic: Probing the Properties of Atoms, Molecules, and Solids". The course will focus on experimental techniques in atomic and condensed matter physics. It will emphasize the common physical concepts that are applicable from relatively simple atoms to complex solids. The course will draw on the research experience of the physics faculty at Wesleyan. The course will also be offered to high school teachers enrolled as summer students in the Graduate Liberal Studies Program at Wesleyan. This course will prepare both undergraduates and high school teachers to work in the research labs either during the school year or during a subsequent summer. ***