Beyond Binary: Understanding Multi-State Stability in Ferroelectrics

非技术描述：人们希望创建在“超越二进制”意义上起作用的设备，这意味着它们可以访问和利用多个状态（不仅仅是“0”？和今天标准计算机的“1”）来完成逻辑、存储器和其他功能。这样的系统可以模拟类似大脑的功能，并导致我们如何进行计算和存储数据的变革。这种方法对材料有严格的要求，这些材料目前还不容易获得。这些包括基于该材料的固有特征可以表现出多个、精确且唯一可寻址的“微观状态”的材料，该材料必须不随时间显著波动或退化。确定能够以这种方式发挥作用的合适材料仍然是一个首要挑战。该项目探索铁电材料，这些材料具有内在稳定性和快速性，但传统上只表现出二元（而不是多态）功能，以找到创建多态功能的新途径。该项目提供了对一系列应用重要的材料的新的基本理解，扩展了我们对如何合成和控制对一系列下一代应用至关重要的复杂候选材料的知识，为新技术开发提供了基础理解，包括对神经形态，超材料，逻辑/存储器和能量转换应用的潜在影响，在尖端材料和实验方法方面培训和教育现代劳动力，同时深化我们合成/制造复杂材料的能力，从而实现新的知识产权和创业努力。技术能力：访问多个配置状态（即，超越二进制）将使我们如何进行计算和存储数据发生变革。神经形态计算架构（设计用于模拟大脑中的神经元功能）需要基于可读的宏观有序参数呈现出多个、精确且唯一可寻址的“微观状态”的材料，该宏观有序参数不会随时间显著波动或退化。需要新的适应性材料来实现这种变革性技术。确定合适的材料-结构，化学，形态和随机性-使真正的神经形态（多状态）的原则仍然是一个首要的挑战。该计划通过先进材料合成，制造和表征的创新组合探索基本材料设计，控制和理解的各个方面，以实现内在双稳态铁电材料中的新颖，多态功能。该研究通过了解如何控制铁电体中的极化、静电、梯度、弹性和其他能量，研究了从随机到确定性生产非易失性多状态的过渡路线。这是通过以下方式实现的：1）使用外延生长来产生复杂的多基态畴结构，其中长程集体相互作用实现多个状态; 2）开发设计者应变和能量景观，其实现化学不均匀膜中的非易失性多状态稳定性;以及3）合成和施加电场和应力以基于缺陷-极化耦合来诱导多状态配置。该研究提供了关于铁电性的本质以及如何控制极化，如何以不断提高的精度生产复杂的多组分材料，铁电开关如何在系统中演变以及如何在固态材料中实现多态功能的基础见解。该项目还提供了高科技研究人员的培训和教育，为代表性不足的学生群体提供研究机会，并可以使重要技术在一系列重要技术领域发挥重要作用。

NON-TECHNICAL DESCRIPTION: There is desire to create devices that function in a "beyond binary" sense - meaning that they can access and make use of multiple states (not just the "0s"? and "1s" of standard computers today) to complete logic, memory, and other function. Such systems could emulate brain-like function and lead to transformative changes in how we do computation and store data. Such approaches have stringent requirements for materials which are not readily available today. These include materials that can exhibit multiple, precisely and uniquely addressable "microstates" based on an intrinsic feature of that material which must not fluctuate or degrade significantly over time. Identifying suitable materials that can function in this manner remains a foremost challenge. This project explores ferroelectric materials, which are intrinsic stable and fast, but have traditionally exhibited only binary (not multi-state) function to find new routes to create multi-state function. This project provides new fundamental understanding of materials that are important for a range of applications, expands our knowledge of how to synthesize and control complex, candidate materials critical for a range of next-generation applications, provides foundation understanding for novel technological development including potential impact on neuromorphic, metamaterial, logic/memory, and energy transduction applications, and trains and educates a modern workforce in cutting-edge materials and experimental approaches while deepening our abilities to synthesize/fabricate complex materials thereby enabling new intellectual property and entrepreneurial endeavors.TECHNICAL DETAILS: The ability to access multiple configuration states (i.e., going beyond binary) in materials will enable transformative changes in how we do computation and store data. Neuromorphic computing architectures (designed to emulate neuron function in the brain) require materials exhibiting multiple, precisely and uniquely addressable "microstates" based on a readable macroscopic order parameter which does not fluctuate or degrade significantly over time. New adaptable materials are required to enable such transformative technologies. Identifying suitable materials - structures, chemistries, morphologies and stochasticities - that enable true neuromorphic (multi-state) principles remains a foremost challenge. This program explores aspects of fundamental materials design, control, and understanding through an innovative combination of advanced materials synthesis, fabrication, and characterization to enable novel, multi-state function in intrinsically bi-stable ferroelectric materials. The research investigates routes to transition from stochastic to deterministic production of non-volatile multi-states by understanding how to control the polarization, electrostatic, gradient, elastic, and other energies in ferroelectrics. This is achieved by 1) using epitaxial growth to produce complex, multi-ground state domain architectures wherein long-range collective interactions enable multiple states; 2) developing designer strain and energy landscapes that enable non-volatile, multi-state stability in chemically-inhomogeneous films; and 3) synthesis and application of electric field and stress to induce multi-state configurations based on defect-polarization coupling. The research provides foundational insights about the nature of ferroelectricity and how polarization can be controlled, how to produce complex, multi-component materials with ever-increasing precision, how ferroelectric switching evolves in systems, and how multi-state function can be achieved in solid-state materials. This project additional provides for training and education of high-tech researchers, research opportunities for underrepresented student groups, and could enable technologies of importance to a range of important technical fields.