Nature of Emergent Interface and Hetero-structure Properties of Oxides
讲座名称：
Nature of Emergent Interface and Hetero-structure Properties of Oxides
讲座时间：
2015-06-15
讲座人：
Jiandi Zhang
形式：
校区：
兴庆校区
实践学分：
讲座内容：
题目: Nature of Emergent Interface and Hetero-structure Properties of Oxides
时间: 2015年06月15日 16:00
地点: 中一楼3113
报告人: Jiandi Zhang
报告摘要：
A defining characteristic of complex transition-metal compounds (TMCs), such as cuprates, manganites, ruthenates, and Fe-based superconductors, is that they contain incomplete d sub-shells thus having a multiple of possible ground states. This triggers their vast variety of physical properties, emerging from electrons with strong orbital characteristics and correlations through the close coupling with lattice and spin degrees of freedom. On one hand, both chemical and physical complexity presents a formidable challenge in condensed matter physics and materials science in general. On the other hand, the complexity is directly responsible for their tunability in displaying fascinating quantum properties, which are mainly arising from a complicated competition between multiple energy scales. Such competition makes the system extremely sensitive to external stimuli, offering a fabulous playground for making artificial structures of these materials with new functionalities. One can anticipate that new physics will emerge when ultrathin layers of TMCs are grown into artificial heterostructures with electronic and magnetic properties manipulated by broken symmetry and modified interface couplings“the interface is a platform.”
In the past few years, it has become increasingly clear that surfaces, interfaces, thin films and heterostructures of TMCs display a rich diversity of fascinating properties that are related, but not identical to, the bulk phenomena, while the origin is still fiercely contested. In many cases, controlling the quality of interfaces and films of these complex materials is the essential step toward the understanding. In this talk, I will discuss about the emergent physical properties and their possible origin of a prototype oxide in ultrathin film form and its interface with other oxides. In particular, I will discuss the nature of thickness-driven metal-to-insulator transition in the films of La2/3S1/3MnO3 (LSMO). Based on our recent studies by atomically controlled growth and characterization with Low Energy Electron Diffraction, Angle-resolved X-ray photoelectron spectroscopy, scanning tunneling and scanning transmission electron microscopy/spectroscopy, I will discuss the surface termination, layer-by-layer variation of composition and structure distortion, and their profound effect on the electronic and magnetic property, including the emergent insulating behavior in ultrathin films.
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