Topological phases and curvature-driven pattern formation in cholesteric shells

Soft Matter, vol. 19, pp. 1987–2000

Abstract

We study the phase behaviour of cholesteric liquid crystal shells with different geometries. We compare the cases of tangential anchoring and no anchoring at the surface, focussing on the former case, which leads to a competition between the intrinsic tendency of the cholesteric to twist and the anchoring free energy which suppresses it. We then characterise the topological phases arising close to the isotropic-cholesteric transition. These typically consist of quasi-crystalline or amorphous tessellations of the surface by half-skyrmions, which are stable at lower and larger shell sizes, respectively. For ellipsoidal shells, defects in the tessellation couple to a local curvature, and according to the shell size, they either migrate to the poles or distribute uniformly on the surface. For toroidal shells, the variations in the local curvature of the surface stabilise heterogeneous phases where cholesteric or isotropic patterns coexist with hexagonal lattices of half-skyrmions.

Authors 5

1. Giuseppe Negro

   Istituto Nazionale di Fisica Nucleare, Sezione di Bari · University of Bari Aldo Moro

   Affiliation as printed

   Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy

2. Livio Nicola Carenza corresponding Aachen Instituut-Lorentz

   Leiden University

   Affiliation as printed

   Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands

3. Giuseppe Gonnella

   Istituto Nazionale di Fisica Nucleare, Sezione di Bari · University of Bari Aldo Moro

   Affiliation as printed

   Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy

4. Davide Marenduzzo

   University of Edinburgh

   Affiliation as printed

   SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK

5. Enzo Orlandini

   University of Padua

   Affiliation as printed

   Dipartimento di Fisica e Astronomia, Università di Padova, 35131 Padova, Italy