The London Center For The Theory And Simulation Of Materials
Ab initio electronic screening: A key to improved DFT accuracy and to new ab initio predictions
Density functional theory codes have focused on calculating ground state properties of static systems without external perturbations. It is well known from work on screened Hartree-Fock, GW, MP2, and RPA approximations that improved accuracy can be obtained by calculating the system's screening in response to perturbations. However these improvements are very computationally heavy, and often have been reserved to quantum chemistry codes.
We describe our work within the CASTEP plane-wave DFT code to calculate the spin-charge susceptibility, which describes the system's screening. Our method is computationally light: we are able to calculate the screening response to a perturbation with a time and memory cost similar to that of a traditional DFT calculation of the Kohn-Sham ground state. It also highly scalable on parallel computers. This capability allows (1) calculations of screened Hartree-Fock and (in the near future) GW, (2) more robust convergence of the DFT ground state calculation, and (3) prediction of dynamic response properties. Our algorithm for screened Hartree-Fock and GW is new, and features a much reduced memory consumption. We finish by discussing how this approach could be used to calculate properties of spintronics materials, including charge and spin transport.
Dr. Sacksteder has a long term research experience on quantum transport calculations. He has developed both analytical and computational techniques applying them in particular to topological materials and graphene. He has received his PhD in theoretical physics with Giorgio Parisi at Sapienza Universita Di Roma, has been working as a postdoctoral researcher at APCTP Postech, Pohang, South Korea, at the Chinese Academy of Sciences in Beijing and at Nanyang Technological University in Singapore.
Prof. Dr. Stefan Kettemann | Prof. of Physics | Physics & Earth Sciences | Focus Area Health
Phone: (0421) 200 -3521 | E-Mail: s.kettemann [at] jacobs-university.de