报告人简介： 

　　李飞博士本科及博士分别毕业于西安交通大学（2006年、2012年）。2012年7月至今，在西安交通大学电子系工作，历任讲师、副教授。2015年10月至2018年6月，在美国宾夕法尼亚州立大学从事研究工作，历任博士后、research associate（合作导师：Long-Qing Chen、Thomas R. Shrout）。李飞博士长期从事高性能铁电、压电材料与器件的研究工作，同时利用相场模拟的方法辅助相关材料的设计和性能分析。他已发表SCI论文80余篇，其中40余篇文章以第一作者或通讯作者发表在 Nature Materials，Nature Communications，Advanced Materials，Applied Physics Letters等重要期刊上，所发表SCI论文的总引用次数为2500余次。李飞博士受邀在国际学术会议做邀请报告7次。   

　　报告摘要： 

　　The discovery of ultrahigh piezoelectricity in relaxor ferroelectric solid solution single crystals, e.g. PMN-PT, has led to their implementation in high performance medical ultrasound transducers and underwater sonar.  A key signature of relaxor-ferroelectrics is the existence of polar nano regions (PNRs), a nano-scale inhomogeneity that coexists with normal ferroelectric domains.  The contribution of these local structures has been theoretically modeled to be the origin of the ultra-high piezo activity.  Based on the paradigm, recent developments have experimentally confirmed that modest changes in the polarizability of PNRS can be regarded as “seeds” to further enhance the piezoelectric activity of relaxor ferroelectrics.  Both modified polycrystalline and single crystals have been shown to exhibit ultra-high piezo d₃₃- coefficients.  Furthermore, dielectric permittivities greater than 10,000 and relatively good temperature stability have been achieved.  The impact of these property improvements on applications, including ultrasound transducers and sensors, will be presented.