Double helical defects in smectic A and smectic A* phases

作者：Meyer C; Logbo H; Briouel B; Picot J C; Nastishin Yu A^*; Kleman M

来源：Liquid Crystals, 2010, 37(8): 1047-1057.

DOI：10.1080/02678291003782846

• chiral smectic A
• defects
• double helices
• screw dislocations

Double helical (DH and DH*) domains, defects of the smectic A (SmA) phase, have for the first time been studied in the smectic A* (SmA*) phase, composed of chiral molecules. Both left- and right-handed DH*s are found in SmA*s, but not in equal numbers. The majority of the DH*s in the two left-handed cholesterics studied are left-handed, whereas in the SmA phase of non-chiral molecules the DHs are left- and right-handed in equal numbers. DHs and DH*s, which are topologically screw dislocations of giant Burgers vectors, appear to be significantly distorted with respect to a geometrically ideal model. It has been shown that imperfections in the DH*s and DHs are covered by a combination of three types of elementary distortions. The relation between the pitch in DH* and DH and temperature is discussed.

• 出版日期2010