NOTE THIS IS A MONDAY (SPECIAL SEMINAR)
I will present some of our recent work on the understanding of Charge Density Wave (CDW) instabilities of several materials, by means of Density Functional Theory (DFT) calculations. The presentation will focus on the correlation between the crystal structure and the electronic properties, with special emphasis on the structural instabilities which have an electronic origin. I will present results for the blue bronze, K0.3MoO3, a tradicional system in which the CDW is originated by a Peierls instability. For this material, the Lindhard response function computed from DFT is able to account quantitatively for the Peierls scenario. I will also show results in connection with recent experimental studies that have been able to demonstrate the presence of charge density waves in several 2D single-layer materials like NbSe2, TiSe2 and TiTe2. For NbSe2, we have focused on the nature and atomic displacements associated with the CDW. The evolution of the CDW with external electrostatic doping, which has been achieved experimentally using field effect transistor setups, will be analysed for the case of TiSe2. For the case of TiTe2, we focus on the recently observed CDW in the single layer, which is not present in the bulk material.