CAREER: Towards universal understanding of caloric and other complex effects in ferroics from multiscale modeling

该职业奖通过基于计算第一性原理的对各种铁材料中的磁热、电、弹性和多热效应的探索，支持计算研究和教育。热效应与在施加或去除外场时温度的可逆绝热变化有关，并可能为固态制冷技术提供基础，固态制冷技术是传统制冷的一种节能和环保替代品。近年来，由于在某些材料中发现了巨大的热效应，以及对能量转换和能源可再生材料的兴趣增加，对固体中的热效应的兴趣急剧增加。然而，对巨大热量反应的机制和相互作用的基本理解是有限的。该项目的最终目标是通过多尺度建模方法对铁材料的热效应有一个基本的了解。为了达到这个目标，PI将。1 .开发一种多尺度计算工具，允许在不同长度尺度范围内精确模拟各种铁质的热量响应；2 .对各种铁质材料的电热、磁热和弹热效应进行综合研究；利用材料特定的多尺度计算工具来设计和预测具有增强热响应的材料。该研究将与研究生和本科生的教育以及初高中学生的外展活动相结合。通过将计算项目整合到计算物理和物理中的数学方法这两门课程中，PI将丰富研究生和本科生的课程。PI将为参与研究的研究生提供计算物理方面的教育和培训。PI最近为中学生设立了一个外展项目。该奖项支持外展计划的进一步发展以及研究生参与该计划。作为该计划的一部分，中学生每年将访问物理系，并在他们的学校主持PI的小组。外展计划的一个特别之处在于让学生早早接触到令人兴奋的科学世界。CAREER奖支持计算探索如何将变化的电场、磁场、应力场或场的组合应用于某些材料，从而导致温度变化。从基础科学的角度来看，这些热效应，即电热效应、磁热效应、弹性热效应和多热效应都是有趣的，并且可能在固态制冷技术中得到应用，这是传统制冷的一种节能和环保的替代品。热量效应几十年前就已经为人所知；然而，它们似乎是不切实际的，因为观察到的温度变化很小。最近的实验证明了多种巨大的热效应，需要重新评估这些热效应在实际应用中的潜力。该奖项支持旨在建立从人体尺度到原子尺度的热量效应基本机制的研究。PI计划开发一个理论基础和工具，用于可靠，快速和廉价的计算机探索和设计热量材料。这些结果可能会导致固态制冷领域的重大进展。潜在的应用包括但不限于传感器和芯片上制冷的紧凑和便携式冷却；住宅和车辆的制冷/空调；以及多功能磁电子器件。此外，纳米级铁材料的研究可能会通过冰箱的小型化对制冷技术产生影响，从而提高效率，减少重量和体积，以及环保制冷剂将极大地造福社会。结合研究计划，将开展教育和外展活动，使研究及时渗透到教育中，并激励新一代的科学家和工程师：(1)将计算研究纳入至少两门课程；(2)研究生将成为研究的一部分；(3)开展外展活动，对中学生进行科学职业教育。

TECHNICAL SUMMARYThis CAREER award supports computational research and education through a computational first-principles-based exploration of magnetocaloric, electrocaloric, elastocaloric, and multicaloric effects in a wide range of ferroic materials. Caloric effects are associated with a reversible adiabatic change in the temperature under either an application or removal of external fields and may provide the basis for solid-state refrigeration technology - an energy-efficient and environmentally friendly alternative to conventional refrigeration. In recent years interest in caloric effects in solids has dramatically increased, thanks to the discoveries of giant caloric effects in some materials as well as the elevated interest in energy-converting and energy-renewable materials. However, fundamental understanding of the mechanisms and interactions underlying giant caloric responses is limited. The ultimate goal of this project is to reach a fundamental understanding of caloric effects in ferroic materials through a multiscale modeling approach. To reach this goal, the PI will1. develop a multiscale computational tool that allows accurate simulations of caloric responses in a variety of ferroics and across a span of length-scales;2. carry out comprehensive research on electrocaloric, magnetocaloric and elastocaloric effects in various ferroics;3. utilize the materials-specific multiscale computational tools to work towards designing and predicting materials with enhanced caloric responses. The research will be integrated with the education of graduate and undergraduate students as well as an outreach activity with middle school and high school students. The PI will enrich both graduate and undergraduate curriculum through the integration of computational projects in two courses: Computational Physics and Mathematical Methods in Physics. The PI will provide both education and training in computational physics to the graduate students involved in the research. The PI has recently established an outreach program for middle school students. This award supports further growth of the outreach program as well as involvement of graduate students in the program. As part of the program the middle school students will visit the physics department annually as well as host the PI's group in their school. A special feature of the outreach program is the early exposure of students to the exciting world of science. NONTECHNICAL SUMMARYThe CAREER award supports the computational exploration of how the application of a changing electric field, magnetic field, stress field, or a combination of fields to some materials can lead to a change in temperature. These caloric effects, the electrocaloric, magnetocaloric, elastocaloric, and multicaloric effects respectively are interesting from a fundamental science point of view, and may have applications in solid-state refrigeration technology - an energy-efficient and environmentally friendly alternative to conventional refrigeration. Caloric effects have been known for decades; however, they seemed to be impractical because the observed changes in temperature were small. Recent experiments have demonstrated multiple giant caloric effects requiring a reassessment of the potential of these caloric effects for practical application.The award supports research aimed to establish the fundamental mechanisms of caloric effects across the scales from the human scale to the scale of atoms. The PI plans to develop a theoretical foundation and the tools for a reliable, fast and inexpensive computer exploration and design of caloric materials. These outcomes may lead to a considerable advance at the frontiers of solid-state refrigeration. The potential applications include but are not limited to compact and portable cooling for sensors and on-chip refrigeration; refrigeration/air conditioning for dwellings and vehicles; and multifunctional magneto-electronic devices. Furthermore, the research on nanoscale ferroic materials may have impact on refrigeration technology through miniaturization of refrigerators, where increased efficiencies, reduced weight and volume, and environmentally friendly refrigerants would greatly benefit society. In conjunction with the research plan, education and outreach activities will be undertaken to achieve timely penetration of research into education, and to inspire a new generation of scientists and engineers: (1) computational research will be integrated into at least two courses; (2) graduate students will be a part of the research; (3) an outreach activity will be performed to educate middle school students about careers in science.