Can Koçer

Research

I develop first-principles computational methods and apply them to problems in materials science and condensed matter physics. My two main areas of focus are (1) density-functional theory (DFT) simulations of lithium-ion battery electrode materials, and (2) method development of phonon and electron-phonon coupling calculations for correlated materials with DFT+DMFT. Some highlights from my published work:

Complex Oxide Electrode Materials: A major focus of my research have been the Wadsley-Roth (crystallographic shear) phases, a promising class of Nb-based lithium-ion battery electrodes. These complex oxides have attracted attention for their ability to intercalate and deintercalate lithium very quickly, enabling fast-charging batteries. I have used DFT to study the electronic structure, cation disorder, lithium insertion mechanism, and lithium diffusion of these materials. These simulations led to detailed atomic-scale insights into the origin of the fast-charging behaviour by identifying the diffusion mechanism: a network of coupled, one-dimensional tunnels with low activation barriers allow rapid lithium motion.

Lattice Dynamics with DFT+DMFT: Phonons play a fundamental role in the physics of solids. DFT calculations of phonons allow us to understand phonon-driven phenomena from first-principles, but their usefulness depends on how well the electronic structure of a material is described by DFT. We have developed a method to calculate phonons in correlated materials, using DFT+DMFT instead of DFT as the electronic structure method (see illustration on the right). This allows us to study temperature-driven effects on phonons that are purely due to electronic correlation, for example close to metal-insulator transitions.