(1) School of Physics and Astronomy, University of Manchester, M13 1PL Manchester, UK;(2) School of Physics and Astronomy, University of Minnesota, 55455 Minneapolis, MN, USA;(3) Brookhaven National Laboratory, NSLS, 11973 Upton, NY, USA
Abstract:
A binary mixture of an antiferroelectric liquid-crystal material containing a selenium atom and a highly chiral dopant is
investigated using resonant X-ray scattering. This mixture exhibits a remarkably wide four-layer intermediate smectic phase,
the structure of which is investigated over a temperature range of 16K. Analysis of the resonant X-ray scattering data allows
accurate measurement of both the helicoidal pitch and the distortion angle as a function of temperature. The former decreases
rapidly as the SmC* phase is approached, whilst the latter remains constant over the temperature range studied at 8°±3° . We also observe that the senses of the helicoidal pitch and the unit cell of the repeating four-layer structure are opposite
in this mixture and that there is no pitch inversion over the temperature range studied.