Aug 22, 2016

「On tetrahedratic order and chiral symmetry breaking」
Prof. Helmut R. Brand


講演題目: On tetrahedratic order and chiral symmetry breaking
講 師 : Prof. Helmut R. Brand
     Department of Physics, University of Bayreuth, Germany
日 時 : 平成28年8月22日 (月) 16:00-17:00
場 所 : 北海道大学理学部2号館2-211室

要 旨 :
We investigate how tetrahedratic order can influence chirality in nonchiral systems. For nematic phases composed of achiral bent-core molecules the occurence of chiral domains of opposite hand is well-established experimentally [1,2] and has been modeled as being due to a linear gradient term between quadrupolar and octupolar order [3]. Recently there have been experimental results not only on liquid crystals, but also on optically isotropic phases. It turns out that in such materials mesoscopic to macroscopic domains of either hand can occur spontaneously [4]-[7]. We argue [8] that transient elasticity coupled to tetrahedratic order can lead to chiral domains of opposite hand in an optically isotropic system even for achiral molecules. This issue is related to the question of chiral symmetry breaking in condensed matter physics, but also potentially relevant for biological systems. [1] G. Pelzl et al., J. Mater. Chem. 12, 2591 (2002) [2] T. Niori, J. Yamamoto, and H. Yokoyama, Mol. Cryst. Liq. Cryst. 409, 475 (2004) [3] H.R. Brand, H. Pleiner, and P.E. Cladis, Physica A 351. 189 (2005); H.R. Brand and H. Pleiner, Eur. Phys. J. E 31, 37 (2010); H. Pleiner and H.R. Brand, Eur. Phys. J. E 37, 11 (2014). [4] M. Jasinski, D.Pociecha, H. Monobe, J. Szczytko, and P. Kaszynski, J. Am. Chem. Soc. 136, 14658 (2014). [5] C. Dressel, T. Reppe, M. Prehm, M. Brautzsch, and C. Tschierske, Nat. Chem. 6, 971 (2014). [6] C. Dressel, W. Weissflog, and C. Tschierske, Chem. Comm. 51, 15850 (2015). [7] M. Alaasar, M. Prehm, Y. Cao, F. Liu, and C. Tschierske, Angew. Chem. Int. Ed. 55, 312 (2016). [8] H.R. Brand and H. Pleiner, to be published

世話人  北 孝文
北海道大学理学部物理学科 (電話011-706-3484)

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