Electron Correlations and the Properties of Metals and Insulators

这个理论项目包含凝聚态物理中的几个相关组成部分。第一种是关于微观和介观物体之间长程和短程相互作用的密度泛函理论。密度泛函理论(DFT)提供了一种计算分子和材料的电子和几何结构的方法，这些分子和材料太大了，波函数方法无法实用。密度泛函理论在高密度凝聚态和共价键分子的计算中取得了很大的成功。然而，在长程范德华(VDW)或色散相互作用结合的物质的应用中，它通常是失败的。稀疏物质，包括软凝聚物质、多种类型的层状凝聚物质、许多有机复合体和生物物质的重要组成部分，都是遥不可及的。首席研究员已经找到了有希望纠正这个问题的方法，这项研究将进一步测试和发展这些方法。将应用于层状固体、有机物，甚至生物物质，如核酸DNA和RNA。该项目的第二个组成部分是使用所谓的量子蒙特卡罗(QMC)方法来处理VDW络合物。这是一种基于计算机采样的电子结构计算方法，可以得到具有已知精度的结果。虽然它本身是一种重要的电子结构方法，但它将被用来补充现有的波函数计算，以验证新发展的密度泛函方法的准确性。第三个部分是试图理解作为单电子晶体管的量子点中的输运，量子点由嵌入在半导体表面金属层中的非常小的人造结构组成。智力上的优点：对VDW相互作用的密度泛函理论的研究有可能加深我们对这些重要和普遍存在的力的理解。关于QMC的补充工作是一个重要的验证工具。单电子晶体管的研究包括凝聚态物理中的基本概念和问题。更广泛的影响：发展一种有效的VDW相互作用DFT将具有广泛的应用和重要意义。对量子点中输运的理解将影响纳米电子学。该项目将为学生和博士后伙伴提供极好的培训。这个凝聚态物理的理论研究项目涉及开发理解原子、分子和固体的电子结构的方法。特别是，这些方法将适用于组件交互较弱且范围较长的系统。这种弱相互作用系统的例子包括许多有机物质，包括生物系统。因此，这一项目的成功完成可以产生广泛的影响。在另一个单独的项目中，将研究量子点中电子的行为。这可以使人们更好地理解纳米电子学的基础。这项研究为学生和博士后助理提供了极好的培训。

This theoretical project contains several related components in condensed matter physics. The first is a density functional theory of both long-range and short-range interaction between microscopic and mesoscopic bodies. Density functional theory (DFT) provides a method for the calculation of the electronic and geometric structures of molecules and materials that are too large for wave-function methods to be practical. DFT has been very successful in calculations on high density condensed matter and on covalently bonded molecules. However, it has generally failed in applications to matter bonded by long-range van der Waals (vdW) or dispersion interactions. Sparse matter, including soft condensed matter, many types of layered condensed matter, many organic complexes, and important parts of biological matter, have been out of reach. The principal investigator has found methods which show promise for rectifying this problem, and this research will further test and develop them. Applications to layered solids, organic matter, and even biological matter, such as the nucleic acids DNA and RNA, will be carried out. The second component of the project is the use of the so-called quantum Monte Carlo (QMC) method on vdW complexes. This is a method of electronic structure calculation based on computer sampling, which can obtain results with a known accuracy. Although it is an important electronic structure method in its own right, it will be used to supplement existing wave-function calculations for the validation of the accuracy of the new density functional methods developed. The third component will be an attempt to understand transport in quantum dots acting as single electron transistors and consisting of very small artificial structures embedded in metallic layers on semiconductor surfaces.Intellectual merit: The research on DFT for vdW interactions has the potential to further our understanding of these important and ubiquitous forces. The complementary work on QMC is an important validation tool. The study of single electron transistors includes fundamental concepts and issues in condensed matter physics.Broader Impact: Development of an effective DFT for vdW interactions will have wide application and importance. Understanding of transport in quantum dots will impact nanoelectronics. The project will provide excellent training for students and postdoctoral associates.%%%This theoretical research project in condensed matter physics deals with developing methods to understand the electronic structure of atoms, molecules and solids. In particular, the methods will apply systems in which components interact weakly and over long range. Examples of such weakly interacting systems include much of organic matter, including biological systems. Thus, successful completion of this project can have wide impact. In a separate project the behavior of electrons in quantum dots will be studied. This can lead to a better understanding of the foundations of nanoelectronics The research provides excellent training for students and postdoctoral associates.***