Static-lattice calculations have been employed to model the phases of VO 2 and V 1-δ W δ O 2 . Interatomic potentials were empirically fitted to reproduce the low-and high-temperature phases (monoclinic and tetragonal, respectively) of vanadium dioxide as well as the monoclinic phase of tungsten dioxide. For pure VO 2 , we located the soft modes of the high-temperature phase, which characterize the initial atomic displacements that lead to the displacive phase transition to the low-temperature phase. The T ) 0 structure of the saddle point, where only half of the one-dimensional chains have undergone Peierls distortions, and the ionic motion along the lowest-energy path for the phase transition are described. For V 1-δ W δ O 2 , we found that doping significantly stabilizes the high-temperature phase relative to the low-temperature phase, which explains the observed depression in the transition temperature as δ increases. For the highand low-temperature phases, the local structures about the dopant, which were obtained by employing a Mott-Littleton approach, resembled those of the low-and high-temperature phases, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.