title: Mechanically induced biaxial transition in a nanoconfined nematic liquid crystal with a topological defect.
abstract: Using an atomic force microscopy, we have measured the separation dependence of the force between an atomically flat mica sheet and a micrometer-sized glass sphere immersed in the nematic liquid crystal. As the mica surface induces a strong parallel alignment and the treated glass sphere induces a strong perpendicular alignment on the liquid crystal, a repulsive force is observed due to the elastically deformed nematic liquid crystal. We observe that below a critical separation d(th) approximately 10 nm, the system undergoes a structural transition, thus relaxing the distortion. The results are interpreted within the eigenvalue exchange mechanism using the Landau-de Gennes tensorial approach.
authors.affiliation: CNR-INFM LiCryL, c/o Physics Department, University of Calabria, 87036 Rende (CS), Italy. giovanni.carbone@eng.ox.ac.uk
authors.forename: Giovanni
authors.initials: G
authors.lastname: Carbone
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lombardo
authors.forename: Riccardo
authors.initials: R
authors.lastname: Barberi
authors.forename: Igor
authors.initials: I
authors.lastname: Musevic
authors.forename: Uros
authors.initials: U
authors.lastname: Tkalec