Seminar: "Quantum Materials at the atomic scale: Visualization and Designing" Dr. Yoshinori Okada

Speaker:

Dr. Yoshinori Okada

Advance Institute for Material Research (AIMR)

Tohoku University, Japan

Title: "Quantum Materials at the atomic scale: Visualization and Designing"

Abstract

One of the most critical challenges at the frontier of materials physics is the ability to control band structure, both for realizing novel phenomena and for practical functionalities. In this talk, I will describe our atomic scale investigations of novel quantum materials called topological crystalline insulators (TCIs) [1-5]. In TCIs, topology and crystal symmetry intertwine to create massless Dirac electrons, which can be described by the same equations used for relativistic particles travelling close to the speed of light. Using Landau level spectroscopy and atomic resolution imaging in TCIs, we have discovered massive Dirac electrons coexisting with massless Dirac electrons [2,5]. Our findings experimentally demonstrate the unique and extraordinary tunability of Dirac electrons in TCIs, which provides a significant step for realizing fundamentally and practically important quantum states via strain engineering. As the final part of this talk, I will also introduce my recent attempt of combing visualization technique with thin film based material design.

[1]  Liang Fu, Phys. Rev. Lett. 106, 106802 (2011)

[2]  Y. Okada et al., Science 14, 318 (2013)

[4]  I. Zeljkovic, Y. Okada et al., Nature Phys., 10, 572 (2014)

[5]  I. Zeljkovic, Y. Okada et al., Nature Mater., 14, 318 (2015)

Biography

Yoshinori Okada is currently an assistant professor at advanced institute of materials research (AIMR) at Tohoku University. His interests lie in atomic scale investigation of novel phenomena and functionalities in quantum materials. He has dual capabilities in single particle spectroscopies and epitaxial thin film growth. He received his B.Sc. and Ph. D. from Nagoya University in 2004 and 2009, respectively. His Ph.D. thesis was on investigating the mechanism of high temperature superconductivity in copper oxide compound. Soon after getting Ph.D., he became a postdoctoral researcher at Massachusetts Institute of Technology (MIT) and Boston College (BC), totally for four years. In 2013, he became an assistant professor at Tohoku University.