title: Two-dimensional skyrmions and other solitonic structures in confinement-frustrated chiral nematics.
abstract: We explore spatially localized solitonic configurations of a director field, generated using optical realignment and laser-induced heating, in frustrated chiral nematic liquid crystals confined between substrates with perpendicular surface anchoring. We demonstrate that, in addition to recently studied torons and Hopf-fibration solitonic structures (hopfions), one can generate a host of other axially symmetric stable and metastable director field configurations where local twist is matched to the surface boundary conditions through introduction of point defects and loops of singular and nonsingular disclinations. The experimentally demonstrated structures include the so-called "baby-skyrmions" in the form of double twist cylinders oriented perpendicular to the confining substrates where their double twist field configuration is matched to the perpendicular boundary conditions by loops of twist disclinations. We also generate complex textures with arbitrarily large skyrmion numbers. A simple back-of-the-envelope theoretical analysis based on free energy considerations and the nonpolar nature of chiral nematics provides insights into the long-term stability and diversity of these inter-related solitonic field configurations, including different types of torons, cholestric-finger loops, two-dimensional skyrmions, and more complex structures comprised of torons, hopfions, and various disclination loops that are experimentally observed in a confinement-frustrated chiral nematic system.
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Ackerman
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Rahul P
authors.initials: RP
authors.lastname: Trivedi
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Bohdan
authors.initials: B
authors.lastname: Senyuk
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and National Renewable Energy Laboratory, Golden, Colorado 80401, USA and Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Jao
authors.initials: J
authors.lastname: van de Lagemaat
authors.affiliation: Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA and Liquid Crystal Materials Research Center and Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, USA and Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Ivan I
authors.initials: II
authors.lastname: Smalyukh
mesh_terms: D004601:Elementary Particles; D005898:Glass / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D055620:Optical Phenomena; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D017971:Tin Compounds; C109984:indium tin oxide