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

Brown University, Providence RI

Investigators

Abstract

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.