Complex Phenomena in Ferroelectrics and Multiferroics from First Principles

该奖项支持的研究项目旨在：(1)研究块状铁电材料和铁电纳米复合材料中的复杂现象，(2)模拟和理解简单块状、固溶体和超薄形式的多铁材料的静态和动态特性，以及(3)设计具有理想和新特性的新型偶极材料。研究目标将通过开发和使用以下最先进的从头计算数值工具来解决：(i)第一性原理技术，（ii）有效的哈密顿方法，通过真实地模拟铁电体和多铁体在有限温度下的静态和动态特性来扩展第一性原理计算的范围，以及（iii）逆方法，允许具有改进性能的材料的有效设计。将加强与欧洲知名研究小组的现有合作，这些研究小组在铁电体和多铁体方面有重要的实验计划。阿肯色大学和欧洲伙伴之间拟议的合作活动将允许在预测和测量之间进行仔细的并排比较，这对于充分了解要研究的系统和改进要开发的数值工具非常重要。由于需要开发和使用的技术的多样性，以及需要研究的系统的多样性，预计将获得对复杂现象，纳米科学和偶极系统相变的广泛而深入的了解。该研究项目将通过以下方式融入学生的教育体验：(i)通过阿肯色大学和法国巴黎中央学院的联合博士项目对他们进行计算和实验物理方面的培训；（ii）组织每周一次的视频会议，以及欧洲合作者和阿肯色大学之间的定期访问；（iii）将铁电体和多铁体的最新研究成果纳入凝聚态物理课程。倡议亦会吸引代表性不足的学生积极参与拟议项目，以增加多元化。铁电体具有自发的电极化，这种极化可以通过施加电场而逆转。这些材料对于各种设备应用都很重要，例如将电脉冲转换为机械振动的“压电换能器”，将能量转换为各种运动的执行器，即使在没有电源的情况下也能保留存储信息的“非易失性存储器”，以及用于微电子和无线通信的介电材料。类似地，多铁质材料是一类很有前途的材料，它表现出铁电性和磁性之间罕见的共存，这可能被证明对设计新器件非常有用。铁电性和多铁性材料的一些相关问题目前尚不清楚。本奖项支持的研究项目旨在：(1)研究铁电材料中的复杂现象，(2)建模和理解多铁材料的几种特性，以及(3)设计具有理想和新特性的新材料。PI将开发和使用各种计算技术来实现这些目标。将加强与欧洲知名研究小组的现有合作，这些研究小组在铁电体和多铁体方面有重要的实验计划。阿肯色大学和欧洲伙伴之间拟议的合作活动将允许在预测和测量之间进行仔细的并排比较，这对于充分了解要研究的系统和改进要开发的数值工具非常重要。由于要开发和使用的技术的多样性，以及要研究的系统的多样性，预计将获得复杂现象，纳米科学和相变的广泛而深入的知识。除了建立一个网络，作为未来相关机构之间合作和交换学生的基础之外，合作的努力也有可能导致实现具有改进和/或新功能的设备，这些设备可以积极影响生活质量，提高能源效率和储存。该研究项目将通过以下方式融入学生的教育体验：(i)通过阿肯色大学和法国巴黎中央学院的联合博士项目对他们进行计算和实验物理方面的培训；（ii）组织每周一次的视频会议，以及欧洲合作者和阿肯色大学之间的定期访问；（iii）将铁电体和多铁体的最新研究成果纳入凝聚态物理课程。倡议亦会吸引代表性不足的学生积极参与拟议项目，以增加多元化。

TECHNICAL SUMMARYThis award supports a research program that is aimed at: (1) investigating complex phenomena in bulk ferroelectric materials and ferroelectric nanocomposites, (2) modeling and understanding static and dynamical properties of multiferroics in their simple bulk, solid solution, and ultrathin forms, and (3) designing new dipolar materials with desirable and new properties. The research objectives will be tackled through the development and use of the following state-of-the-art and ab initio numerical tools: (i) first-principles techniques, (ii) effective Hamiltonian approaches that extend the reach of first-principles calculations by realistically mimicking static and dynamical properties of ferroelectrics and multiferroics at finite temperature, and (iii) the inverse method that allows an efficient design of materials with improved properties.Existing collaborations with well-known European research groups who have a vital experimental program on ferroelectrics and multiferroics will be strengthened. The proposed cooperative activities between the University of Arkansas and the European partners will allow a careful side-by-side comparison between predictions and measurements, which is important to fully understand the systems to be investigated, and to refine the numerical tools to be developed. A broad and deep knowledge of complex phenomena, nanoscience and phase transitions in dipolar systems is expected to be gained thanks to the diversity of techniques to be developed and used, and the variety of systems to be investigated.This research program will be integrated into the educational experience of students by: (i) training them in computational and experimental physics via a joint Ph.D. program between the University of Arkansas and Ecole Centrale de Paris in France, (ii) organizing a weekly video conference as well as regular visits between the European collaborators and the University of Arkansas, and (iii) incorporating recent research findings on ferroelectrics and multiferroics into Condensed Matter Physics classes. The PI will also aim at increasing diversity by attracting students from underrepresented groups to be active players of the proposed projects.NONTECHNICAL SUMMARYFerroelectrics possess a spontaneous electric polarization that can be reversed by applying an electric field. These materials are of importance for a variety of device applications, such as "piezoelectric transducers" that convert electrical pulses to mechanical vibrations and vice versa, actuators that convert energy into various kinds of motion, "non-volatile memories" that retain stored information even when not powered, and dielectrics for microelectronics and wireless communication. Similarly, multiferroics form a promising class of materials that exhibits a rare coexistence between ferroelectricity and magnetism that may be prove to ve very useful for designing novel devices. Several materials related issues in ferroelectrics and multiferroics are presently unknown. The present award supports a research program that is aimed at: (1) investigating complex phenomena in ferroelectric materials, (2) modeling and understanding several properties of multiferroics, and (3) designing new materials with desirable and new properties. The PI will develop and use various computational techniques to achieve these goals. Existing collaborations with well-known European research groups who have a vital experimental program on ferroelectrics and multiferroics will be strengthened. The proposed cooperative activities between the University of Arkansas and the European partners will allow a careful side-by-side comparison between predictions and measurements, which is important to fully understand the systems to be investigated, and to refine the numerical tools to be developed. A broad and deep knowledge of complex phenomena, nanoscience and phase transitions is expected to be gained thanks to the diversity of techniques to be developed and used, and the variety of systems to be investigated. In addition to building a network that will be the basis for future collaborations and exchange of students between the involved institutions, the collaborative efforts also have the potential to result in the realization of devices with improved and/or new functionalities that can positively affect quality of life and improve energy efficiency and storage.This research program will be integrated into the educational experience of students by: (i) training them in computational and experimental physics via a joint Ph.D. program between the University of Arkansas and Ecole Centrale de Paris in France, (ii) organizing a weekly video conference as well as regular visits between the European collaborators and the University of Arkansas, and (iii) incorporating recent research findings on ferroelectrics and multiferroics into Condensed Matter Physics classes. The PI will also aim at increasing diversity by attracting students from underrepresented groups to be active players of the proposed projects.