Symmetry Classes of Spin and Orbital Ordered States in a t_{2g} Hubbard Model on a Two-dimensional Square Lattice

This paper presents symmetry classes of the Hartree-Fock (HF) solutions of spin and orbital ordered states in a t_{2g} Hubbard model on a two-dimensional square lattice. Using a group theoretical bifurcation theory of the Hartree Fock equation, we obtained many types of broken symmetry solutions which bifurcate from the normal state through one step transition in cases of commensurate ordering vectors Q_0=(0,0), Q_1=(\pi,\pi), Q_2=(\pi,0) and Q_3=(0,\pi). Each broken symmetry state is characterized by the presence of local order parameters(LOP) at each lattice site: quadrupole moment Q=(Q_2^2,Q_{12},Q_{23},Q_{31}), orbital angular momentum l=(l_1,l_2,l_3), spin density s=(s^1,s^2,s^3), spin quadrupole moment Q^{\lambda}=(Q_2^{2\lambda}, Q_{12}^{\lambda},Q_{23}^{\lambda},Q_{31}^{\lambda}) and spin orbital angular momentum l^{\lambda}=(l_1^{\lambda},l_2^{\lambda},l_3^{\lambda}) where \lambda=1,2,3. We performed numerical calculations for some parameter sets. Then we have found that many types of non-collinear magnetic orbital ordered states having LOP:Q^{\lambda} and l^{\lambda} can be the ground state for these parameter sets.Comment: 46 pages with 4 figure

Electrically tunable lasing based on defect mode in one-dimensional photonic crystal with conducting polymer and liquid crystal defect layer

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Ryotaro Ozaki, Yuko Matsuhisa, Masanori Ozaki, and Katsumi Yoshino, Appl. Phys. Lett. 84, 1844 (2004) and may be found at https://doi.org/10.1063/1.1686891

Laser actions in nano-helical-structured liquid crystals

Optical Science and Technology, the SPIE 49th Annual Meeting, 2004, Denver, Colorado, United StatesMasanori Ozaki, Ryotaro Ozaki, Tatsunosuke Matsui D.D.S., and Katsumi Yoshino "Laser actions in nano-helical-structured liquid crystals", Proc. SPIE 5518, Liquid Crystals VIII, (15 October 2004). DOI: https://doi.org/10.1117/12.55554

Linearly polarized lasing in one-dimensional hybrid photonic crystal containing cholesteric liquid crystal

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Yuko Matsuhisa, Ryotaro Ozaki, Yuuki Takao, and Masanori Ozaki, J. Appl. Phys. 101, 033120 (2007) and may be found at https://doi.org/10.1063/1.2434835

Electrically color-tunable defect mode lasing in one-dimensional photonic-band-gap system containing liquid crystal

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Ryotaro Ozaki, Tatsunosuke Matsui, Masanori Ozaki, and Katsumi Yoshino, Appl. Phys. Lett. 82, 3593 (2003) and may be found at https://doi.org/10.1063/1.1577829

High Q defect mode and laser action in one-dimensional hybrid photonic crystal containing cholesteric liquid crystal

The authors have investigated the optical characteristics of a one-dimensional hybrid photonic crystal (1D HPC) containing cholesteric liquid crystal (CLC) as a defect by theoretical calculation and predicted the appearance of additional modes at the band edges of the CLC defect, whose Q factor was higher than those of the other defect modes. They have confirmed the appearance of the additional mode experimentally. Single-mode laser action with low pumping threshold was observed in a 1D HPC with a dye-doped CLC defect, which is based on the additional defect mode with a high Q factor peculiar to the CLC defect having periodic structure. This work is partially supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Yuko Matsuhisa, Ryotaro Ozaki, Katsumi Yoshino, Masanori Ozaki, Appl. Phys. Lett. 89, 101109 (2006) and may be found at https://doi.org/10.1063/1.2347114