Summer REU Experience: Olivia Sablan

Wednesday, September 9, 2020

This summer I had the opportunity to conduct research through the Clean Energy Bridge to Research Program with the University of Washington. Due to COVID19, this research experience for undergraduates (REU) was moved to an online program. I virtually worked with Ting Cao, Assistant Professor of Materials Science & Engineering, in his materials theory group to design and engineer two-dimensional nanomaterials by first-principle calculations. To celebrate the summer research completed at UW, each student participated in a brief lightning talk discussing our findings for the University of Washington’s Virtual Summer Research Symposium.

I learned so much about materials science and theoretical work during this research experience. The skills I acquired while working with UW’s supercomputer will be helpful for future computational work that I hope to do in graduate school. I am so thankful that I had the opportunity to participate in this program, and I could not have been successful in this program this summer without the endless support of Carroll’s chemistry department.

Engineering Janus Magnetic Two-Dimensional Materials by First-Principle Calculations

Olivia Sablan, Senior, Chemistry, Carroll College
Ting Cao, Department of Materials Science & Engineering
Kaichen Xie, Department of Materials Science & Engineering
Jimin Qian, Department of Materials Science & Engineering
Clean Energy Bridge to Research REU

Two-dimensional (2D) nanomaterials have become a significant area in materials research today. The widely studied family of 2D semiconductors, transition-metal dichalcogenides (TMDs), has the same atomic species in its top and bottom surface in their natural form. In this work, we explore the possibility of synthesizing artificial Janus magnetic TMD monolayer with the two surfaces consisting of different atomic species. Such Janus materials may hold great potential owing to their unique structural, piezoelectric, conductive, chemical, etc. properties. By first-principle calculations within the density functional theory (DFT), we investigated a prototypical 2D magnet, VSSe. The Janus VSSe monolayer was expected to be synthesized by substitution of Se atoms for top layer S atoms in a VS2 monolayer with the assistance of H atoms. The reaction was calculated to be overall exothermic, and the energy barrier during the removal of top layer S atoms in the form of H2S was obtained. These results were further compared with similar reactions that occurred in Janus MoSSe. Our results also show that Janus VSSe could be a potential piezoelectric magnet, as it holds intrinsic electric polarization between the surfaces. The study of Janus VSSe opens the doors to exploring other 2D Janus magnetic structures with interesting properties, such as novel magneto-optical effects and efficient photovoltaics. Presentation.