UVSOR Lunch Seminar (2004-12)

Date&Time: March 2nd, 12:00-12:35
Place: UVSOR Build. #304 (User's room)

Speaker: Professor Tae W. Noh

Affiliation: ReCOE, School of physics, Seoul National University, Seoul, Korea

Title: Roles of orbitals in transition metal oxides probed by optical spectroscopy


Abstract: Mott-Hubbard systems with degenerate orbitals are of particular interest,
as the orbital degeneracy effect is strong and the charge dynamics is dominated by
electronic correlations. It has been a long standing mystery that the optical absorption
features of low energy state in Mott insulators, such as titanites, vanadates, cobaltates,
ruthenates, and molybdates, could not be simply understood in terms of the ‘U’ peak
. Recently, we found that such a mystery could be explained when the full orbital
multiplicity effects are taken into account [1,2]. In this talk, we will discuss how
we could understand the roles of orbitals in transition metal oxides from the optical
spectra. Especially, we want to discuss how the orbitals could determine physical
properties, such as magnetic and transport properties, of numerous 3d and 4d
transition metal oxides.

[1] J. S. Lee et al., Phys. Rev. Lett. 89 257402 (2002).
[2] M. W. Kim et al., Phys. Rev. Lett. 92 27202 (2004).