Electronic and Magnetic Mechanisms in Low-Dimensional and Novel Materials

提议的活动是研究电子各向异性在分子晶体材料中的作用。这种各向异性影响这些材料的金属、超导、磁性和绝缘状态。提出的工作的主要目的是：比较实验和计算电子各向异性的影响；利用物理方法控制各向异性的程度以产生新的电子态；为了更清楚地理解低维系统中超导是如何产生的；探讨各向异性材料中的量子极限效应；将传统的费米表面研究扩展到30 T以上的脉冲磁场的新区域；并考虑在这些材料的强磁场和高压下进行物理测量的推测性新方法。分子晶体是电子（导电）材料科学技术中的新兴领域。它们连接了半导体、金属和生物结构领域。与硅或铜等传统固体不同，这些固体是由排列成简单的三维有序阵列的原子组成的，方向之间几乎没有区别，而分子晶体是由排列成链或层的大分子（通常是有机分子）组成的。因此，分子晶体的电子性质在固体内部的三个方向上可能是非常不同的（各向异性）。这种各向异性影响了它们的超导、磁性和半导体性能。提出的研究目的是通过实验和计算研究各向异性在结晶分子固体中的作用，包括使用电子，磁性，压力和光学探针来测量和操纵它们的物理性质。了解各向异性影响这些性质的机制，将有助于设计和合成本课程中具有特别理想物理性质的新材料。＊＊＊

9510427 Brooks The proposed activity is the investigation of the role of electronic anisotropy in molecular crystalline materials. This anisotropy influences metallic, superconducting, magnetic, and insulating states in these materials. The main objectives of the proposed work are: to compare experimentally and computationally the effects of electronic anisotropy; to manipulate the degree of anisotropy by physical means to produce new electronic states; to understand more clearly how superconductivity arises in low-dimensional systems; to explore quantum limit effects in anisotropic materials; to extend traditional Fermi surface studies into new regimes of pulsed magnetic fields above 30 T; and to consider speculative new methods of physical measurement in intense magnetic fields and very high pressures in these materials. %%% The area of molecular crystals is an emerging one in the science and technology of electronic (electrically conducting) materials. They link the realms of semiconductors, metals, and biological structures. Unlike traditional solids such as silicon or copper which are composed of atoms arranged in simple three-dimensional ordered arrays, with little or no distinction between directions, molecular crystals are composed of large (usually organic) molecules arranged in either chains or layers. Hence, the electronic properties of molecular crystals can be very different (anisotropic) in the three directions within the solid. This anisotropy affects their superconducting, magnetic, and semiconducting properties. The purpose of the proposed research is to investigate experimentally and computationally the role of anisotropy in crystalline molecular solids, including the use of electronic, magnetic, pressure, and optical probes to measure and manipulate their physical properties.. An understanding of the mechanisms by which anisotropy influences these properties wi ll lead to the design and synthesis of new materials in this class having particularly desirable physical properties. ***