Acquisition of a High-Magnetic-Field/Low-Temperature Facility for Materials Research with Synchrotron X-Rays

格雷文同步加速器X射线散射在材料科学和凝聚态物理中发挥着越来越重要的作用。该合同为购置几乎独一无二的强磁场/低温设施提供部分支持，该设施将在美国的主要同步辐射X射线源之一--斯坦福同步辐射实验室(SSRL)运行。这一新设备将允许研究具有同步加速器产生的X射线所特有的高动量分辨率的新材料的结构和磁性，磁场高达13特斯拉，温度超过三个数量级，0.3K-400K。科学计划涉及对电子-电子相互作用发挥重要作用的材料的研究。这种“相关电子”材料处于凝聚态物理学的前沿，它们为发现、观察和表征新的基本现象提供了无数的可能性。例如，具有钙钛矿结构的电荷载流子掺杂反铁磁性绝缘体中的强电子-电子关联导致了如下各种性质：(I)绝缘体-金属相变，(Ii)高温超导电性，(Iii)巨磁电阻，(Iv)电荷有序相，(V)和自旋有序相。在这些体系中，结构、磁性和电性通常是紧密耦合的，而磁场的存在往往会导致新的相。这项科学计划涉及电荷、共振磁性和非共振磁性X射线散射技术。它还将包括现场传输测量，以获得同时的结构、磁性和电子信息。此外，它还将受益于涉及单晶的生长和表征、中子散射实验以及与斯坦福大学正在进行的光电子能谱工作的合作的补充研究。因此，这一新的高磁场/低温同步加速器X射线设备将使投标人能够进行材料科学和凝聚态物理前沿的研究，并有助于培养具有材料科学、应用科学和物理背景的新一代本科生和研究生。

9802737GrevenSynchrotron X-ray scattering plays an increasingly important role in materials science and condensed matter physics. This award provides partial support for the acquisition of a nearly unique high-magnetic-field/low-temperature facility to be operated at one of the Nations's major synchrotron X-ray sources, the Stanford Synchrotron Radiation Laboratory (SSRL). This new facility will allow the study of structural and magnetic properties of novel materials with the high momentum-resolution unique to synchrotron-generated X-rays, at magnetic fields up to 13 Tesla, and over more than three orders of magnitude in temperature, 0.3K T 400K.The scientific program involves the study of materials in which electron-electron interactions play an important role. Such "correlated-electron" materials are at the frontier of condensed matter physics, and they provide myriad possibilities to discover, observe, and characterize nove fundamental phenomena. For example, the strong electron-electron correlations in charge-carrier-doped antiferromagnetic insulators with perovskite-derived structures are known to lead to such diverse properties as: (i) insulator-metal transitions, (ii) high-temperature superconductivity, (iii) colossal magnetoresistance, (iv) charge-ordered phases, (v) and spin-ordered phases. The structural, magnetic, and electronic properties are generally intimately coupled in these systems, and the presence of a magnetic field often leads to new phases. The scientific program involves charge, resonant magnetic, and non-resonant magnetic X-ray scattering techniques. It will furthermore involve in situ transport measurements to obtain simultaneous structural, magnetic, and electronic information. Moreover, it will benefit from complementary research involving the growth and characterization of single crystals, neutron scattering experiments, and the collaboration with the ongoing photoemission spectroscopy effort at Stanford. This new high-magnetic-field/low-temperature synchrotron X-ray facility will thus allow the invesitgator to conduct research at the forefront of materials science and condensed matter physics, and it will help educate a new generation of undergraduate and graduate students with materials science, applied science, and physics backgrounds.%%%***