From atoms and molecules to solids… A glimpse into my research journey so far…
It is a well-known fact that every material in the universe is composed of atoms, which in turn comprise nuclei and electrons. A comprehensive understanding of the interactions among such sub-atomic particles have enabled us to tailor materials for a plethora of applications that heavily govern our day-to-day living. Thanks to advances in computation and theory development, investigating these interactions systematically has been possible. Based on the type of system, different computational methods are used to achieve this. For example, at the atomic scale, quantum chemistry simulations implemented within a localized orbital (or atomic orbital) basis set are performed routinely. On the other hand, for periodic solids, density functional theory (DFT) generally implemented within a plane-wave basis set, is used. Obviously, the list of methods is not restricted to those mentioned above. My talk will attempt to cover my journey so far, where I have been exposed to both perspectives of thinking. I will be providing a glimpse of my current work on time-dependent thermally-assisted-occupation DFT (TDTAO-DFT) which is a low-cost method to study excited states. This method is based on a modified DFT scheme known as TAO-DFT, which explicitly incorporates the non-dynamical correlation effect in ground-state simulations, but retains the low computational complexity of conventional DFT. In line with the title of my presentation, which coincides with the reverse chronology of my research journey, I will present my earlier works on solid state simulations using phosphorene (a quasi–two-dimensional sheet of phosphorus atoms) as an example. Here, I will be demonstrating how the electronic properties are tuned without affecting its excellent transport properties as well mechanical and structural stability.