Argonne National Laboratory

Abstract：

Epitaxial films' surfaces and interfaces have become a vibrant research focus in material science, where intricate details of the atomic structure play a pivotal role in determining a variety of emergent properties. The development of the COherent Bragg Rod Analysis (COBRA) method facilitates the reconstruction of a complete electron density profile in interfacial systems, including epitaxial thin films, heterostructures, and quantum dots. Here I’ll illustrate examples showcasing the acquisition of precise structural information for oxide epitaxial thin films. Firstly, I will present the results of in situ synchrotron X-ray measurements conducted during the epitaxial growth of SrTiO3 on SrTiO3 (001), both with and without bilayer graphene as an intermediate layer. Secondly, I will talk about the discovery of the origin of the 2D electron gas (2DEG) at the SrTiO3 (001) surface and its evolution. Our findings reveal that the 2DEG only appears when the surface has TiO2 double layer structure. Intriguingly, by deposition of single layer of SrO or the subsequent growth of a TiO2 monolayer, we are able to completely control the disappearance/reappearance of the 2DEG, potentially providing a means of manipulating 2DEG-behavior in oxide electronics.

Reference:

[1] Xi Yan et al., APL Materials, 10(9):091114, 2022

[2] Xi Yan et al., Advanced Materials, 34(24):2200866, 2022

Brief CV of Dr. Xi Yan:

Xi Yan is currently a postdoctoral researcher in the Materials Science Division at Argonne National Laboratory. She earned her Ph.D. in condensed matter physics from University of Chinese Academy of Sciences.

腾讯会议ID:  198-997-333

会议密码：0129

主  持  人：李洋沐  特聘研究员

联  系  人：傅    琦（82649469）