We extensively study the possibility of p doping in the ferroelectric host material BiFeO₃ via cation (A- and B-site) and anion doping. Promising candidates according to the resulting electronic structure and formation energies are identified and the role of oxygen vacancies is explored.  Read more 

We study topological materials, featuring protected degeneracy in the electron structure of insulators and metals. Collaborating with Prof. Kane and Prof. Male in the Department of Physics, University of Pennsylvania, we have discovered novel topological states, such as three-dimensional Dirac semimetals, Dirac line node semimetals, and double Dirac semimetals. We also have predicted robust materials that should realize the proposed topological phases. The figure illustrates Dirac line nodes.  Read more 

Experimental results have shown promising catalytic activity for the oxygen evolution reaction (OER) on the perovskite-type material CaMnO₃. Through density functional theory investigations, we study the OER mechanism on CaMnO₃, on the basis of a thermodynamic stability approach. Our results reveal that the formation of Mn vacancies caused by the solubility of Mn enhances lattice oxygen activity, which then reduces the energy of the adsorbate *OOH and therefore loosens the lower overpotential limit predicted from the “scaling relationship”. This effect suggests that, by doping manganite oxides with soluble elements, we could enhance their OER catalytic activities due to the high surface lattice oxygen activity induced by surface metal ion vacancies. Read more