Prediction of Raman spectra with DFT plus U method

The linear response formulation of the Raman susceptibility based on density functional theory (DFT) has been extended to the DFT + U approach to treat strong correlation effects for localized electrons. The Hubbard model parameters required in the DFT + U calculation are also determined using the linear response method. The present scheme contains no adjustable parameters and therefore allows an ab initio prediction of the Raman spectra for strongly correlated systems. The method is applied to cathode materials for lithium ion batteries, LiCoO2 and LiNi1/2Mn3/2O4. The Raman spectra for these compounds are remarkably improved by the Hubbard correction with DFT + U, making the spectra in much better agreement than the standard DFT with the experiments. The present approach provides an accurate and efficient prediction of the Raman spectra for correlated systems.