Date: Tuesday, September 21, 2021
Time: 11:00 am
Talk Title: Mechanical properties of graphene-like systems
We were first ( see Mechanical properties of graphene and boronitrene, Phys Rev B, Vol. 85, No. 12 (2012), to define a new material property for two-dimensional systems such as graphene (single layer graphite) that we named the layer modulus. This is the 2D equivalent of the 3D bulk modulus. Using first principles quantum mechanical means, we calculated the layer modulus of graphene to be 206.6 Nm-1. Comparing the layer modulus with other graphene-like materials, such as 2D BN, SiC, Si and so on, we were able to show that the purely carbon-based system was strongest in the two-dimensional , and most resilient to isotropic compression and stretching. We also explored 2D pressure-induced phase transitions in these systems and concluded that negative pressure is more likely to result in a phase transition since compression is likely to lead to buckling. This is an area that is still very open to new investigations, both from a theoretical and experimental point of view. We speculate on the possibilities for the future.
Prof. Nithaya Chetty is a theoretical and computational physicist with research interests in the quantum mechanical properties of electrons in solids. His areas of focus over the past decade have mostly been in two-dimensional (2D) graphene-like materials. His paper on the mechanical properties of graphene and boronitrene published in 2012 with his students in the American Physical Society Physical Review has been cited more than 350 times.
In this work, the authors defined a new physical property for 2D materials and were the first to demonstrate that graphene is the hardest material known to humans from a 2D compressibility point of view. He is currently Vice President of the International Union for Pure and Applied Physics, and a member of the Academy of Science of SA. He served as the president of the South African Institute of Physics from 2007 to 2009.
Prof. Chetty served as the Deputy Chief Executive Officer of the National Research Foundation (NRF) overseeing the Astronomy portfolio during the build phase of the MeerKAT Radio Telescope. He was an American Fulbright Fellow for his graduate studies at the University of Illinois in 1985, and subsequently for research leave in the US 20 years later. He received the NRF President’s Award in 1997.
He has written and spoken publicly on the importance of maintaining an intellectually free environment at our universities and has been a strong advocate for academic freedom.