title: Nematic twist-bend phase with nanoscale modulation of molecular orientation.
abstract: A state of matter in which molecules show a long-range orientational order and no positional order is called a nematic liquid crystal. The best known and most widely used (for example, in modern displays) is the uniaxial nematic, with the rod-like molecules aligned along a single axis, called the director. When the molecules are chiral, the director twists in space, drawing a right-angle helicoid and remaining perpendicular to the helix axis; the structure is called a chiral nematic. Here using transmission electron and optical microscopy, we experimentally demonstrate a new nematic order, formed by achiral molecules, in which the director follows an oblique helicoid, maintaining a constant oblique angle with the helix axis and experiencing twist and bend. The oblique helicoids have a nanoscale pitch. The new twist-bend nematic represents a structural link between the uniaxial nematic (no tilt) and a chiral nematic (helicoids with right-angle tilt).
authors.affiliation: Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA.
authors.forename: V
authors.initials: V
authors.lastname: Borshch
authors.forename: Y-K
authors.initials: YK
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Xiang
authors.forename: M
authors.initials: M
authors.lastname: Gao
authors.forename: A
authors.initials: A
authors.lastname: Jákli
authors.forename: V P
authors.initials: VP
authors.lastname: Panov
authors.forename: J K
authors.initials: JK
authors.lastname: Vij
authors.forename: C T
authors.initials: CT
authors.lastname: Imrie
authors.forename: M G
authors.initials: MG
authors.lastname: Tamba
authors.forename: G H
authors.initials: GH
authors.lastname: Mehl
authors.forename: O D
authors.initials: OD
authors.lastname: Lavrentovich