Phase-Field Model of Inhomogeneous Ferroelectric Crystals Under Ultrafast Stimuli

非技术总结该奖项支持理论研究，计算建模和教育，旨在更好地理解铁电材料。铁电体包括一类晶体材料，其在许多类型的设备中具有重要的技术应用，例如医疗和水下换能器、传感器、非易失性存储器、节能冷却。 该研究计划的目标是开发必要的材料理论和计算机代码，以了解这些铁电晶体在受到外部超快刺激时的反应，例如突然的温度上升或其表面的电场脉冲。研究人员还将探索由于这种外部刺激而可能出现的新材料状态。该小组将利用实验合作者网络来验证开发的理论和计算机代码对实验。所发展的理论和计算机程序可用于描述其他材料系统中的类似现象，例如用于存储器应用的铁磁材料中的超快磁化动力学，以及电子开关器件中新电子相的潜在形成和转变。该项目预计不仅通过推进材料理论对材料科学产生影响，还包括应用数学和材料力学。PI还将把几项教育和推广活动纳入研究;这些活动包括：1）开发材料建模软件的开放源代码版本，并组织相关的年度研讨会，2）招募本科生使用软件包进行研究，以及3）妇女和代表性不足的少数民族通过参与大学，广泛组织的外展活动，并通过招募他们在PI的实验室进行研究。技术总结该奖项支持理论研究，计算建模，以及旨在更好地理解铁电材料的教育。铁电体包括一类晶体材料，其在许多类型的设备中具有重要的技术应用，例如医疗和水下换能器、传感器、非易失性存储器、节能冷却。本研究计划的目标是了解外部超快刺激下的非均匀铁电晶体的动态响应，并在晶体内的域之间存在复杂的静电和弹性相互作用。PI和他的团队将开发一种动态相场方法来建模，预测和理解超快刺激下极化和应变域模式的动态时空演变，同时考虑到远程静电和弹性相互作用以及畴壁能量。该小组还将探索新的瞬态或亚稳态域状态，当非均匀晶体从外部刺激的激发态弛豫回到原始或新的平衡态时可能会出现这些状态;这些状态可能是在热力学条件下通常无法观察到的隐藏状态。研究人员将研究非均匀晶体在超快外部刺激下的铁电和压电响应，并将探索超快频率下的热，电，机械和多功能响应。该小组将利用一个实验合作者网络来验证所开发的理论和计算机代码与实验。所提出的动态相场方法可以扩展到许多其他问题的研究。例如，它可以适用于解决耦合的弹性动力学方程的微磁相场方程，用于探索具有强磁弹性耦合的铁磁材料中的超快磁化动力学。该方法还可以通过引入超快刺激下的电子自由度来研究电子-晶格耦合现象和新电子相的潜在形成，从而允许操纵相关系统中的电子相变，例如金属-绝缘体相变。该项目预计不仅通过推进材料理论对材料科学产生影响，还包括应用数学和材料力学。PI还将把几项教育和推广活动纳入研究;这些活动包括：1）开发铁性材料建模软件的开放源代码版本，并组织相关的年度研讨会，2）招募本科生使用软件包进行研究，以及3）妇女和代表性不足的少数民族通过参与大学，广泛组织的外展活动，并招募他们在PI的实验室进行研究。该奖项反映了NSF的法定使命，并通过评估被认为值得支持使用基金会的知识价值和更广泛的影响审查标准。

NONTECHNICAL SUMMARYThis award supports theoretical research, computational modeling, and education that aim towards better understanding ferroelectric materials. Ferroelectrics comprise a class of crystalline materials that have found important technological applications in many types of devices, such as medical and underwater transducers, sensors, non-volatile memories, energy-efficient cooling. The goal of this research program is to develop the necessary materials theories and computer codes to understand how these ferroelectric crystals respond when subjected to external ultrafast stimuli, such as a sudden temperature rise or an electric-field pulse on their surface. The researchers will also explore possible new material states that may emerge as a result of such external stimulation. The group will utilize a network of experimental collaborators to validate the developed theory and computer codes against experiments. The developed theory and computer codes could find use in describing similar phenomena in other materials systems, for example the ultrafast magnetization dynamics in ferromagnetic materials for memory applications, and the potential formation of and transitions between novel electronic phases in electronic switching devices.The project is expected to have impact not only on materials science by advancing materials theories, but also on applied mathematics and the mechanics of materials. The PI will also integrate several educational and outreach activities into the research; these include: 1) the development of an open-source version of modeling software for materials and the organization of an associated annual workshop, 2) the recruitment of undergraduate students to perform research using the software package, and 3) the engagement of women and underrepresented minorities in STEM via participation in university-wide organized outreach activities and by recruiting them to perform research in the PI's laboratory.TECHNICAL SUMMARYThis award supports theoretical research, computational modeling, and education that aim towards better understanding ferroelectric materials. Ferroelectrics comprise a class of crystalline materials that have found important technological applications in many types of devices, such as medical and underwater transducers, sensors, non-volatile memories, energy-efficient cooling. The goal of this research program is to understand the dynamic responses of inhomogeneous ferroelectric crystals under external ultrafast stimuli and in the presence of complex electrostatic and elastic interactions among domains within the crystal. The PI and his group will develop a dynamical phase-field method to model, predict, and understand the dynamical spatiotemporal evolution of polarization and strain domain patterns under ultrafast stimuli, taking into account long-range electrostatic and elastic interactions and domain-wall energy. The group will also explore novel transient or metastable domain states that may emerge when an inhomogeneous crystal relaxes from its externally stimulated excited state back to the original or a new equilibrium state; these could be hidden states that are normally not observable under thermodynamic conditions. The researchers will investigate ferroelectric and piezoelectric responses of inhomogeneous crystals under ultrafast external stimuli, and will explore thermal, electric, mechanical, and multifunctional responses at ultrafast frequencies. The group will utilize a network of experimental collaborators to validate the developed theory and computer codes against experiments.The proposed dynamic phase-field method can be extended to the study of many other problems. For example, it can be adapted to solve a micromagnetic phase-field equation coupled with an elastodynamic equation for exploring ultrafast magnetization dynamics in ferromagnetic materials with strong magnetoelastic coupling. The proposed approach can also be extended to the study of electron-lattice coupling phenomena and the potential formation of novel electronic phases by introducing electronic degrees of freedom under ultrafast stimuli, allowing the manipulation of electronic phase transitions such as metal-insulator transitions in correlated systems.The project is expected to have impact not only on materials science by advancing materials theories, but also on applied mathematics and the mechanics of materials. The PI will also integrate several educational and outreach activities into the research; these include: 1) the development of an open-source version of modeling software for ferroic materials and the organization of an associated annual workshop, 2) the recruitment of undergraduate students to perform research using the software package, and 3) the engagement of women and underrepresented minorities in STEM via participation in university-wide organized outreach activities and by recruiting them to perform research in the PI's laboratory.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.