Seminars

Abstract: In this talk, I will present our recent theoretical and computational studies on the atomistic phase transition mechanism of two-dimensional materials as a function of stress, along with the new methods developed to study stress modulated phase transition in solid state materials. To demonstrate the ideas and methods, I will start with a model two-dimensional lattice, which has square and hexagonal phases and was originally proposed to study iron transformation from bcc to hcp. Then, I will switch to the two-dimensional transition-metal dichalcogenides (TMDs) using MoTe₂ as an example. Depending on the atom arrangements, 2D TMD appears in two distinct stable phases: the 2H and 1T′ phases. These two phases exhibit completely different electronic structures, with the 2H phase being semiconducting and the 1T′ phase metallic. Our study demonstrated that stress can significantly influence the phase nucleation and propagation in these 2D materials. In turn, the dynamic control of transitions between these two phases through stress field can lead to revolutionary device applications.

Bio: Dr. Wei Gao joined University of Texas at San Antonio in August 2016 as an Assistant Professor of mechanical engineering right after his postdoctoral training at Northwestern University.  He received Ph.D. in Engineering Mechanics from UT Austin in 2014 under the supervision of Dr. Rui Huang. Dr. Gao works on interdisciplinary problems among mechanics, materials and computational science, with current focus on the atomistic and multiscale materials modeling. In 2021, Dr.Gao received NSF CAREER award.