CAREER: Low Loss, Tunable Ferroelectric Thin Films by Pulsed Laser Deposition

9702632习晓星本课题研究的是脉冲激光沉积铁电薄膜的介电非线性和微波损耗。与块体单晶相比，铁电薄膜具有较小的非线性和较高的损耗，其原因尚不清楚。本项目旨在通过关注四个因素的影响来解决这些问题：(1)化学计量；(2)结晶度；(3)界面层和空间电荷；(4)软模声子。这项研究的目的是揭示铁电薄膜在保持高度非线性的同时降低损耗的基本机理。教学计划是为物理学本科实验室课程开发一门“铁电薄膜”实验，该实验包括薄膜沉积、结构和电学特性以及数据分析。这个综合的职业研究和教育项目专注于用于电压可调微波器件的铁电薄膜。这种应用要求铁电薄膜具有较大的介电非线性和较低的微波损耗。本研究旨在揭示影响铁电可调谐微波器件性能的基本机理，以期对铁电可调谐微波器件技术的发展起到一定的作用。该教育计划试图将研究经验纳入物理本科课程。“铁电薄膜”实验将被开发并纳入常规实验室课程，以便学生在这门课程中获得真实的研究体验。***

9702632 Xiaoxing Xi The research of this CAREER project studies the dielectric nonlinearity and microwave losses of ferroelectric thin films deposited by Pulsed Laser Deposition. Compared to bulk single crystals, the nonlinearity of ferroelectric thin films is smaller and the loss is higher, the cause of which is not well understood. This project aims to address these problems by focusing on the effects of four factors: (1) Stoichiometry; (2) Crystallinity; (3) Interface layers and space charges; and (4) Soft-mode phonons. The goal of the research is to reveal the fundamental mechanisms so as to reduce the losses while maintaining a high nonlinearity in ferroelectric thin films. The education plan is to develop a "Ferroelectric Thin Films" experiment for the Physics undergraduate laboratory course, which includes film deposition, structural and electrical characterizations and data analysis. %%% This integrated CAREER research and education project focuses on ferroelectric thin films used in voltage-tunable microwave devices. Such application requires large dielectric nonlinearity and low microwave losses in ferroelectric thin films. This research aims to reveal the fundamental mechanisms that determine these properties in order to improve them thus impacting the development of ferroelectric tunable microwave device technologies. The education plan attempts to incorporate research experience into the physics undergraduate curriculum. A "Ferroelectric Thin Films" experiment will be developed and included in the regular laboratory course so that students can get real-life research experience in this course. ***