RII Track-4:NSF: Synthesis of Oxide Ferroelectric Rashba Semiconductors for Low Power Computing

在机器学习、人工智能和大数据需求的推动下，纳米电子技术预计将在2020年之前消耗世界主要能源的很大一部分。虽然目前的半导体材料和技术面临着满足这些需求的挑战，但使用电子自旋而不是电荷的磁性材料是有前途的替代品。尽管如此，磁自旋信号的有效转换和操纵仍然是一个挑战。这个NSF EPSCoR RII Track-4奖学金项目的目标是通过实验合成和表征一类新材料，这些材料可以使用铁电极化有效地控制和操纵电子自旋，称为铁电Rashba半导体。PI和一名研究生将利用康奈尔大学加速实现、分析和发现界面材料平台（PARADIM）生长设施的最先进的薄膜合成设施来存款候选材料并测量这些系统的性能。这种合作将提高我们对内在自旋-电荷相互转换机制的基本理解，并可能导致内存和计算的新功能。该奖学金计划将建立康奈尔大学和布朗大学之间的长期合作，以培养先进薄膜生长技术的研究生。此外，我们将创建一个双语推广计划，使普罗维登斯高中学生能够探索布朗纳米纤维洁净室。CMOS半导体技术正迅速面临可扩展性、能耗和降低延迟等方面的挑战。这些挑战正在推动开发基于CMOS的技术的替代品以满足未来计算技术的需求的重大努力。自旋电子学利用自旋和电荷的自由度来进行存储和逻辑，是一种很有前途的方法。然而，电荷和自旋信号之间的相互转换仍然效率低下，缺乏对内在自旋-电荷相互转换机制的基本理解。这项研究合作的目标是开发一种新兴的单晶，铁电Rashba半导体（FERSC）的外延氧化物薄膜异质结构，它在室温下利用铁电性和磁性来操纵低功率自旋电子计算范例的自旋-电荷相互转换（SCI）。康奈尔大学最先进的NSF资助的PARADIM分子束外延（MBE）和康奈尔材料研究中心（CCMR），NSF材料研究科学与工程中心（MRSEC），将用于材料合成和表征。在这个项目中，研究人员的目标是优化候选FERSC异质结构的合成，表征它们的结构和铁电特性，将铁电性和Rashba分裂与自旋输运特性相关联。最后，该项目将在合作者和主要研究者及其各自机构之间建立长期合作关系。将通过三个主要机制建立持续的合作：1）PI参与PARADIM用户委员会; 2）在年度PARADIM暑期学校期间PI讲座;和3）康奈尔大学和布朗大学的联合研讨会系列，旨在加强未来的合作和用户从布朗大学到帕拉迪姆。该奖项反映了NSF的法定使命，并已被认为是值得支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。

Driven by demands in machine learning, artificial intelligence, and big data, nanoelectronics are slated to consume a significant portion of the world's primary energy by the end of the decade. While current semiconductor materials and technologies face challenges meeting these demands, magnetic materials, which use the electron’s spin rather than charge, are promising alternatives. Despite this promise, efficient conversion and manipulation of magnetic spin signals remains a challenge. The goal of this NSF EPSCoR RII Track-4 fellowship project is to experimentally synthesize and characterize a new class of materials that can efficiently control and manipulate electron spins using ferroelectric polarization, called ferroelectric Rashba semiconductors. The PI and a graduate student will utilize the state-of-the-art thin film synthesis facilities at Cornell University’s Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM) growth facility to deposit candidate materials and measure the properties of these systems. This collaboration will improve our fundamental understanding of intrinsic spin-to-charge interconversion mechanisms and could lead to new functionalities in memory and computing. This fellowship program will establish a long-term collaboration between Cornell University and Brown University to train graduate students in advanced thin film growth techniques. Furthermore, we will create a bilingual outreach program enabling Providence high school students to explore the Brown nanofabrication clean room.CMOS semiconductor technologies are rapidly facing challenges in scalability, energy consumption, and reduced latency. These challenges are driving a significant effort to develop alternatives to CMOS-based technologies to meet the demands of future computing technologies. Spintronics, which exploits both spin and charge degrees of freedom for memory and logic, is one promising avenue. However, interconverting between charge and spin signals remains inefficient, and a fundamental understanding of intrinsic spin-to-charge interconversion mechanisms is lacking. The objective of this research collaboration is to develop an emergent class of single crystal, epitaxial oxide thin film heterostructures of ferroelectric Rashba semiconductors (FERSCs), which exploit both ferroelectricity and magnetism at room temperature to manipulate spin-to-charge interconversion (SCI) for low power spintronic computing paradigms. Cornell University’s state-of-the-art, NSF-funded PARADIM molecular-beam epitaxy (MBE) and the Cornell Center for Materials Research (CCMR), an NSF Materials Research Science and Engineering Center (MRSEC), will be used for materials synthesis and characterization. In this project, the researcher aims to optimize the synthesis of candidate FERSC heterostructures, characterize their structural and ferroic properties, correlate ferroelectricity and Rashba splitting to spin transport properties. Finally, the project will establish a long-term collaboration between the collaborator and the PI, as well as their respective institutions. A sustained collaboration will be instituted via three main mechanisms: 1) PI involvement in the user committee of PARADIM; 2) PI lecture during the annual PARADIM summer school; and 3) a Cornell PARADIM and Brown University joint seminar series designed to bolster future collaboration and users from Brown to PARADIM.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.