Defects and ordering in nematic coatings on uniaxial and biaxial colloids

We present a systematic lattice Monte Carlo simulation study of nematic ordering in thin nematic shells on uniaxial and biaxial colloidal particles. Typically, four mutually repulsive half-strength defect lines penetrating the shell are observed, as found for spherical particles. For shells of constant thickness, the defect lines tend to accumulate in the high curvature regions. If the thickness of the nematic coating varies across the surface, the defect lines tend to be located in the thinnest regions. On increasing the shell thickness, the defect lines transform into escaped structures with surface point defects.