Features of the Jahn–Teller displacements in LaTiO3 Original Research Article

Atomic displacements involved in a crystal structure of LaTiO3 have been investigated by means of transmission electron microscopy mainly at room temperature. Electron diffraction patterns taken from LaTiO3 were found to be characterized by the presence of the forbidden reflections for the Pnma structure. The extinction rule of these reflections including fundamental ones indicated that a space group of the crystal structure was determined to be P21/a with a monoclinic symmetry. A characteristic feature of the P21/a structure is that there exist the Jahn–Teller atomic displacement with as well as the Jahn–Teller distortion. An additional displacement with should also be needed.