title: Variation of the electronic structure in systematically synthesized Sr2MO4 (M = Ti, V, Cr, Mn, and Co).
abstract: We have systematically synthesized single-crystalline thin films of layered perovskites Sr2MO4 (M = Ti, V, Cr, Mn, and Co) which cannot be obtained in a form of bulk crystal apart from M = Mn. The two-dimensional electronic structure of these M4+ oxides, ranging from a correlated insulator to a ferromagnetic metal, has been investigated by using their optical conductivity spectra with polarizations E is perpendicular to c and E is parallel to c, which reveal systematic variation of the correlated charge gap, Mott-Hubbard gap, or charge-transfer gap. Temperature dependence of the gap-transition spectra is argued in the light of possible spin and/or orbital ordering.
authors.affiliation: Spin SuperStructure Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation, c/o AIST, Tsukuba Central 4, Tsukuba 305-8562, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Matsuno
authors.forename: Y
authors.initials: Y
authors.lastname: Okimoto
authors.forename: M
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura