title: Discovery of a novel smectic-C{*} liquid-crystal phase with six-layer periodicity.
abstract: We report the discovery of a new smectic-C{*} liquid-crystal phase with six-layer periodicity by resonant x-ray diffraction. Upon cooling, the new phase appears between the SmC{alpha}{*} phase having a helical structure and the SmC{d4}{*} phase with four-layer periodicity. This SmC{d6}{*} phase was identified in two mixtures which have an unusual reversed SmC{d4}{*}-SmC{*} phase sequence. The SmC{d6}{*} phase shows a distorted clock structure. Three theoretical models have predicted the existence of a six-layer phase. However, our experimental findings are not consistent with the theories.
authors.affiliation: School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Shun
authors.initials: S
authors.lastname: Wang
authors.forename: Lidong
authors.initials: L
authors.lastname: Pan
authors.forename: R
authors.initials: R
authors.lastname: Pindak
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Liu
authors.forename: H T
authors.initials: HT
authors.lastname: Nguyen
authors.forename: C C
authors.initials: CC
authors.lastname: Huang