Phase-Field Model of Inhomogeneous Ferroelectric Crystals Under Ultrafast Stimuli

非技术总结该奖项支持旨在更好地理解铁电材料的理论研究、计算建模和教育。铁电材料是一类晶体材料，在许多类型的设备中都有重要的技术应用，如医疗和水下换能器、传感器、非易失性存储器、节能冷却等。这项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如何响应，例如突然升温或表面电场脉冲。研究人员还将探索在这种外部刺激下可能出现的新物质状态。该小组将利用一个实验合作者网络，针对实验验证开发的理论和计算机代码。开发的理论和计算机代码可以用来描述其他材料系统中的类似现象，例如用于记忆的铁磁材料的超快磁化动力学，以及电子开关器件中新电子相的潜在形成和转变。该项目预计不仅将通过促进材料理论的发展而对材料科学产生影响，而且将对应用数学和材料力学产生影响。PI还将把几项教育和外展活动整合到研究中；这些活动包括：1)开发材料建模软件的开源版本并组织相关的年度研讨会，2)招募本科生使用该软件包进行研究，以及3)通过参与大学范围内组织的外展活动并通过招募她们在PI的实验室进行研究，让STEM中的妇女和代表性不足的少数群体参与进来。技术总结该奖项支持旨在更好地了解铁电材料的理论研究、计算建模和教育。铁电材料是一类晶体材料，在许多类型的设备中都有重要的技术应用，如医疗和水下换能器、传感器、非易失性存储器、节能冷却等。这项研究的目标是了解非均匀铁电晶体在外部超快刺激下以及晶体内部磁区之间存在复杂的静电和弹性相互作用时的动态响应。PI和他的团队将开发一种动态相场方法来模拟、预测和理解超快刺激下极化和应变域图案的动态时空演变，考虑到长程静电和弹性相互作用以及畴-壁能量。该小组还将探索当非均匀晶体从其外部刺激激发态松弛到原始或新的平衡态时可能出现的新的瞬时或亚稳态；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界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开发的理论和计算机代码与实验的对比。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，它可以适用于求解微磁相场方程和弹性动力学方程，以探索具有强磁弹性耦合的铁磁材料的超快磁化动力学。该方法还可以扩展到研究电子-晶格耦合现象和通过在超快刺激下引入电子自由度来潜在地形成新的电子相，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。该项目不仅将通过促进材料理论的发展而对材料科学产生影响，而且将对应用数学和材料力学产生影响。PI还将把几项教育和外展活动整合到研究中；这些活动包括：1)开发铁质材料建模软件的开源版本，并组织相关的年度研讨会；2)招募本科生使用该软件包进行研究；以及3)通过参与大学范围内组织的外展活动并通过招募她们在PI的实验室进行研究，让妇女和代表性不足的少数群体参与STEM。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.