title: Motion of a colloidal particle in a nonuniform director field of a nematic liquid crystal.
abstract: We investigate the dynamics of a single spherical particle immersed in a nematic liquid crystal. A nonuniform director field is imposed on the substrate by a stripe alignment pattern with splay deformation. The particle of homeotropic anchoring at the surface is accompanied by hyperbolic hedgehog or Saturn-ring defects. The particle motion is dependent on the defect structure. We study the two types of motions theoretically and confirm the obtained results experimentally. The particle accompanied by a hyperbolic hedgehog defect is pulled to a deformed region to relax the elastic deformation energy. The motion occurs in the direction heading the hyperbolic hedgehog defect of a particle in a twist region. The position exhibits a weak S-shaped change as a function of time. The particle accompanied by a Saturn-ring defect shows insignificant motion due to its relatively small deformation energy.
authors.affiliation: Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.
authors.forename: Beom-Kyu
authors.initials: BK
authors.lastname: Lee
authors.affiliation: Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.
authors.forename: Sung-Jo
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.|Bogolyubov Institute for Theoretical Physics of the NAS of Ukraine, Metrolohichna Street 14-b, Kiev 03680, Ukraine.
authors.forename: Bohdan
authors.initials: B
authors.lastname: Lev
authors.affiliation: Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Kim