Louis, L.Gemeiner, P.Ponomareva, I.Bellaiche, L.Geneste, G.Ma, W.Setter, N.Dkhil, B.2011-12-162011-12-162011-12-16201010.1021/nl9034708https://infoscience.epfl.ch/handle/20.500.14299/75609WOS:000276557100015Ferroelectric nanostructures have recently attracted much attention due to the quest of miniaturizing devices and discovering novel phenomena. In particular, studies conducted on two-dimensional and zero-dimensional ferroelectrics have revealed original properties and their dependences on mechanical and electrical boundary conditions. Meanwhile, researches aimed at discovering and understanding properties of one-dimensional ferroelectric nanostruccures are scarce. The determination of the structural phase and of the direction of the polarization in one-dimensional ferroelectrics is of technological importance, since, e.g., a low-symmetry phase in which the polarization lies away from a highly symmetric direction typically generates phenomenal dielectric and electromechanical responses. Here, we investigate the phase transition sequence of nanowires made of KNbO3 and BaTiO3 perovskites, by combining X-ray diffraction, Raman spectroscopy, and first-principles-based calculations. We provide evidence of a previously unreported ferroelectric ground state of monoclinic symmetry and the tuning of the polarization's direction by varying factors inherent to the nanoscale.Ferroelectric nanowiresphase transitiondepolarizing fieldX-ray and Raman analysiseffective HamiltonianBatio3 Nanowires1St PrinciplesTransitionstext::journal::journal article::research article