Transport and Nonequilibrium Effects in Strongly Correlated Multilayer Nanostructure

该奖项支持与强相关多层膜组成的多层器件中传输和非线性效应的处理相关的理论和计算研究以及教育活动。本研究将开发新的形式和计算算法，并将其应用于世界领先的实验小组正在进行实验研究的系统。具体工作包括：（i）开发一种新的数值重整化群计算方法，该方法消除了特别加宽，能够准确处理高能和低能标度，从而能够计算绝缘体和费米液体中的直流输运。(ii)多层体系热电特性的绿色函数密度泛函理论方法的发展。这种技术将被用来制定设计规则，如何保持（或增加）塞贝克效应时，热电材料被纳入多层结构，旨在阻止声子传输。(iii)发展一种精确的非平衡动态平均场理论方法来确定由电流偏置Falicov-Kimball模型描述的多层器件的电流-电压特性。一个强耦合为基础的非平衡杂质问题的方法（类似于连续时间量子蒙特卡罗方法的杂交扩展）处理哈伯德和周期性安德森模型在强耦合和大驱动场也将被检查。(iv)用强关联材料代替介质层或金属板的平行板电容器的强关联效应的研究。这一理论和计算工作将与实验工作相协调，包括德国的约亨·曼哈特的实验工作（电容器），Yuji Matsuda在日本（重费米子多层膜中的电荷和热传输），（接触和大量强相关材料中的开关效应）。该项目支持计算物理学研究生的培训，无论是在学术研究环境中，还是通过在IBM Almaden研究中心为期一年的研究实习。该项目还为本科生提供研究经验，他们将通过在克罗地亚萨格勒布物理研究所的暑期实习了解科学方面的国际合作。通过参与乔治敦大学公共利益科学项目的暑期项目，本科生也将有机会更深入地了解科学和科学家在整个社会中的作用。非技术性总结该奖项支持与电荷和热传输的处理有关的理论和计算研究以及教育活动，这些电荷和热传输由电子与电子相互作用强烈的多层组成。彼此导致高度相关的运动。这些材料对其环境具有很大的敏感性，这使得它们适合用于所谓的智能材料设备，可以改善许多不同电子设备的工作方式。 新的形式主义和计算算法将被开发，然后应用于正在实验研究的系统，由世界各地的领先实验小组。 一些例子包括（i）检查电容如何（储存电荷的能力）可以在这些系统中改变，（ii）检查在尺寸比人类头发小大约100，000倍的这种多层系统中的热感应电流或电流感应热传输，（3）研究欧姆定律如何（它指出电阻器上的电压降与通过它的电流成线性比例）在这些设备中，通过研究所谓的非线性效应，这可能会导致超快电子开关。该项目支持计算物理研究生的培训，无论是在学术研究环境中，还是通过在IBM Almaden研究中心为期一年的研究实习。该项目还为本科生提供研究经验，他们将通过在克罗地亚萨格勒布物理研究所的暑期实习了解科学方面的国际合作。通过参与乔治敦大学公共利益科学项目的暑期项目，本科生也将有机会更深入地了解科学和科学家在社会中的作用。

TECHNICAL SUMMARYThis award supports theoretical and computational research and educational activities related to the treatment of transport and nonlinear effects in multilayered devices composed of strongly correlated multilayers. New formalisms and computational algorithms will be developed and then applied to systems that are being investigated experimentally by leading experimental groups around the world.In particular, the work includes:(i) Development of a new method for numerical renormalization group calculations that removes the ad hoc broadening and is able to accurately treat both high and low energy scales, enabling calculation of dc transport in both insulators and Fermi liquids. (ii) Development of a Green's function based density functional theory approach for determining thermoelectric properties of multilayered systems. This technique will be used to formulate design rules for how to maintain (or increase) the Seebeck effect when thermoelectric materials are incorporated into multilayer structures designed to block phonon transport.(iii) Development of an exact non-equilibrium dynamical mean-field theory approach to determine the current-voltage characteristic of a multilayered device described by a current biased Falicov-Kimball model. A strong-coupling based approach for the non-equilibrium impurity problem (similar to a hybridization expansion for continuous time quantum Monte Carlo approaches) to treat Hubbard and periodic Anderson models at strong coupling and with large driving fields will also be examined.(iv) Investigation of strong correlation effects on the capacitance of a parallel plate capacitor in which the dielectric layers or the metallic plates are replaced by strongly correlated materials. This theoretical and computational work will be coordinated with experimental efforts, including those of Jochen Mannhart in Germany (capacitors), Yuji Matsuda in Japan (charge and heat transport in heavy fermion multilayers), and Doug Natelson at Rice University, US (switching effects in contacts and in the bulk of strongly correlated materials).This project supports the training of graduate students in computational physics, both in the academic research environment and through year-long research internships at the IBM Almaden Research Center. The project also provides research experiences for undergraduate students, who will learn about international collaboration in science through summer internships at the Institute for Physics in Zagreb, Croatia. By engaging in a summer project with Georgetown's Program on Science in the Public Interest, undergraduates will also have the opportunity to gain a deeper understanding of the role of science and scientists in society at large.NONTECHNICAL SUMMARYThis award supports theoretical and computational research and educational activities related to the treatment of charge and heat transport in devices composed of several layers in which electrons interact strongly with each other leading to highly correlated motion. These materials have a large sensitivity to their environment, which makes them suitable for use in so-called smart-material devices which can improve the way many different electronic devices work. New formalisms and computational algorithms will be developed and then applied to systems that are being investigated experimentally by leading experimental groups around the world. Some examples include (i) examining how capacitance (capacity to store charge) can be modified in these systems, (ii) examining heat-induced electrical current or electrical current-induced heat transport in such multi-layer systems of sizes some 100,000 times smaller than the human hair, and (iii) examining how Ohm's law (which states that the voltage drop across a resistor is linearly proportional to the current through it) is violated in these devices by studying the so-called non-linear effects, that could potentially lead to ultrafast electronic switches. This project supports the training of graduate students in computational physics, both in the academic research environment and through year-long research internships at the IBM Almaden Research Center. The project also provides research experiences for undergraduate students, who will learn about international collaboration in science through summer internships at the Institute for Physics in Zagreb, Croatia. By engaging in a summer project with Georgetown's Program on Science in the Public Interest, undergraduates will also have the opportunity to gain a deeper understanding of the role of science and scientists in society at large.