Topological Materials Search Using Theoretical Approaches



Blanchard Professor of Chemistry Professor of Materials Science and Engineering

Project Summary

During this summer I participated in the SURGG program to conduct research in Professor Rappe’s group in the department of Chemistry. Main focus for this summer was to computationally search for materials with interesting topological properties. Recently, topologically nontrivial characteristics in the electronic structure of solids has gained great attention due to its manifestation of diverse and useful physical phenomenon such as spin-polarized current and transport properties. Thus, many condensed matter scientists are very eager to devise useful applications using these topological materials. To search for these types of materials, diverse symmetry constraints are used to design, or search for many candidate materials. Then, computational quantum mechanical code called Density Functional Theory (DFT) calculation is done to calculate for the electronic structure of the specific material. By analyzing the result of the calculation using computational methods, the material is determined to be topological or not. During my summer research experience, I have successfully found a material that host a Dirac point with unusual velocity inversion. From this I have conducted many other calculations to test if it is topological in nature and electronic surface states of this material.

This research experience was a great value for me as it gave me great insight of what is actually being studied outside of the classroom and how the materials I had learned in class applies in actual research. It also gave me a chance to get involved in many scientific writing and presentation of my research. In terms of helping with choosing my career, this research experience gave me the chance to experience what it is like to be a researcher or a graduate student. Doing research was a very different experience from being an undergraduate student, which mostly consists of going to classes, learning the material, and being tested on it. As a researcher, I learned that the answer is usually unknown and many trials and errors are needed to discover the answer.