题 目：DFT and its extensions: strongly correlated systems, superconductors and molecular self-assembly
报告人：Dr. Andrea Floris King’s College London, Strand, WC2R 2LS London, United Kingdom
时 间：2014年11月21日 下午3：00 - 4：30
地 点：理科群2号楼B-409室
Abstract:
An important feature of ab-initio computational methods is the capability to combine accuracy and low computational cost. In this talk, I will illustrate the basic ideas and applications of several, recent density functional theory (DFT) extensions.
I first present a recent scheme to compute the vibrational properties of strongly correlated materials, typically not very well described by standard functionals, by combining two computationally affordable schemes: the Hubbard corrected DFT+U method and the density functional perturbation theory (DFPT). Applications to systems like MnO, NiO and materials of geological interest containing iron will be discussed, showing how the inclusion of the Hubbard U greatly improves the agreement between theory and experiment when computing phonon spectra.
We will then sketch the main concepts of the superconducting DFT (SCDFT), another extension able to predict the critical temperature of conventional superconductors, without the use of empirical parameters.
While these methodologies are mainly applied to bulk materials, a lot of interest is devoted nowadays to low cost functionalization of nanostructured systems by exploiting spontaneous phenomena. In the second part of the talk, we will show various examples of surface functionalization via molecular self-assembly. In particular, we study the properties of metal-organic adlayers of TCNQ molecules deposited with metal atoms on Ag(110), presenting their electrostatic and chiral properties, together with a novel route to fine-tune the surface work function using alkali metals. We then study the covalent assembly of porphyrins on Cu(110), forming very robust nanostructures with a unique directionality, to be possibly exploited in molecular devices operating in extreme conditions.
