Collaborative Research: FuSe: High-throughput Discovery of Phase Change Materials for Co-designed Electronic and Optical Computational Devices (PHACEO)

非技术描述存储和处理数据所需的能源需求正在以不可持续的速度增长。显然需要新技术。相变材料可以在相变过程中显著改变其电子、光学和物理性质，提供了一个很有前途的解决方案。它们的可调性使它们成为新兴应用（如节能内存计算）的有希望的候选者。这个FuSe项目将探索一种新的相变材料，它将五种或更多的元素以相当的数量组合在一起。材料科学领域被这种“高熵”材料的发现所吸引。例如，高熵陶瓷具有独特的热性能和机械性能，这是简单成分所不可能实现的。在这个项目中，研究人员将结合计算材料发现和组合合成来实现高熵相变材料。最有希望的候选材料将被全面表征并集成到电子和光子计算设备中。该团队将建立一个强大的管道来教育下一代劳动力。他们将提供轮岗实习，这样学生就可以在不同的大学和交叉领域工作，并通过指导促进他们的成功。该小组还将在马里兰大学和HBCU的霍华德大学之间建立伙伴关系，以促进研究指导和培训的直接交流。技术描述驱动半导体未来项目的中心假设是，当元素随机占据一种晶格位点并以高浓度存在而不是作为掺杂剂时，高熵相变材料（PCMs）可以形成热力学稳定的单相。这种结构由大的结构熵稳定，将使PCMS的开发具有低/零电阻漂移和大带隙（1.5 eV）或消光系数对比度（∆k~2-3），用于可见光和红外光学忆阻器。拟议的研究包括四个重点课题，将以闭环方式进行。1)第一性原理计算材料发现，以预测以前未探索的熵稳定PCMs。2)硒化物和碲化物的溅射和硫化物的热蒸发组合合成，以便在一次运行中探索多种成分。3)电学、光学、结构和组成材料表征，揭示决定器件性能的内在因素（介电常数、结构、振动模式、组成、电导率、电容等）和外在因素（空隙形成、封盖、几何形状、衬底）。4)将pcm集成到光子和电子器件中，以展示具有最佳性能的光和电忆阻器和忆电容。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical DescriptionThe demand for energy needed to store and process data is growing at an unsustainable rate. New technologies are clearly needed. Phase change materials, which can dramatically change their electronic, optical, and physical properties during phase transitions, offer a promising solution. Their tunability makes them promising candidates for emerging applications such as energy efficient in-memory computing. This FuSe project will explore a new class of phase change materials that combine five or more elements in comparable amounts. The field of materials science has been captivated by the discovery of such “high entropy” materials. For example, high entropy ceramics have unique thermal and mechanical properties not possible with simpler compositions. In this project, investigators will combine computational materials discovery with combinatorial synthesis to realize high entropy phase change materials. The most promising candidates will be characterized comprehensively and integrated into electronic and photonic computational devices. The team will establish a robust pipeline to educate the next-generation workforce. They will offer rotational internships so that students can work at different universities and in cross-cutting fields and promote their success through mentoring. The team will also create a partnership between the University of Maryland and Howard University, an HBCU, to promote the direct exchange of research mentorship and training.Technical DescriptionThe central hypothesis driving this Future of Semiconductors project is that high-entropy phase change materials (PCMs) can form a thermodynamically stable single phase when elements randomly occupy one type of lattice site and are present in high concentrations rather than as dopants. This structure, stabilized by large configurational entropy, will enable development of PCMS with low/zero resistance drift and large bandgaps (1.5 eV) or extinction coefficient contrast (∆k~2-3) for optical memristors in the visible and infrared. The proposed research comprises four thrust topics to be conducted in a closed-loop fashion. 1) First-principles computation material discovery to predict previously unexplored entropy-stabilized PCMs. 2) Combinatorial synthesis via sputtering of selenides and tellurides and thermal evaporation of sulfides in order to explore multiple compositions in a single run. 3) Electrical, optical, structural, and compositional material characterization to reveal the intrinsic (permittivity, structure, vibrational modes, composition, conductivity, capacitance, etc.) and extrinsic (void formations, capping, geometry, substrates) factors dictating device performance. 4) Integration of PCMs into photonic and electronic devices to demonstrate optical and electrical memristors and memcapacitors with optimal performance.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.