Resonant x-ray diffraction study of an unusually large phase coexistence in smectic liquid-crystal films

LiDong Pan; P Barois; R Pindak; Z Q Liu; B K McCoy; C C Huang

doi:10.1103/PhysRevLett.108.037801

Resonant x-ray diffraction study of an unusually large phase coexistence in smectic liquid-crystal films

Phys Rev Lett. 2012 Jan 20;108(3):037801. doi: 10.1103/PhysRevLett.108.037801. Epub 2012 Jan 19.

Authors

LiDong Pan¹, P Barois, R Pindak, Z Q Liu, B K McCoy, C C Huang

Affiliation

¹ School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.

PMID: 22400785
DOI: 10.1103/PhysRevLett.108.037801

Abstract

The recent discovery of the new smectic-C(d6)(*) (SmC(d6)(*)) phase [S. Wang et al., Phys. Rev. Lett. 104, 027801 (2010)] also revealed the existence of a noisy region in the temperature window between the SmC(d6)(*) phase and the smectic-C(d4)(*) (SmC(d4)(*)) phase. Characterized by multiple resonant peaks spanning a wide region in Q(Z), the corresponding structure of this temperature window has been a mystery. In this Letter, through a careful resonant x-ray diffraction study and simulations of the diffraction spectra, we show that this region is in fact an unusually large coexistence region of the SmC(d6)(*) phase and the SmC(d4)(*) phase. The structure of the noisy region is found to be a heterogeneous mixture of local SmC(d6)(*) and SmC(d4)(*) orders on the sub-μm scale.