 previous | upcoming  |
 |
Timo Thonhauser | Department of Materials Science and Engineering I will present our exciting recent developments in (1) orbital magnetization and (2) van der Waals interactions within DFT. Building on these developments, I will then outline my future research plans. (1) Magnetization is a fundamental concept that we teach all undergraduates. Thus, it is truly extraordinary that there was, until our recent work, no generally accepted formula for the orbital magnetization of a periodic solid. Using a Wannier-function approach, we have solved this long-standing problem and derived an analytic quantum-mechanical expression for the orbital magnetization in extended systems [Phys. Rev. Lett. 95, 137205 (2005)]. Our result consists of a Brillouin-zone integral that can be implemented in standard electronic-structure codes. (2) It is well known that van der Waals interactions are not included correctly in the standard form of DFT. We have developed an exchange-correlation functional that includes van der Waals interactions in a seamless manner. The main advantage of our approach is its favorable scaling with system size. We have already successfully calculated the binding energy of two DNA base pairs, and investigations of even larger systems are under way. These developments open up tantalizing possibilities for future research. I will outline the possibility of using the orbital magnetization to calculate NMR shielding tensors. My goal is to apply this new approach to large systems with van der Waals interactions, such as the oligomeric protein aggregates that are toxic in neurological disorders like Alzheimer's and Parkinson's diseases. |