Bulletin of the American Physical Society
2005 APS March Meeting
Monday–Friday, March 21–25, 2005; Los Angeles, CA
Session M5b: Tetrahedratic (Octupolar) Order in Complex Materials |
Hide Abstracts |
Sponsoring Units: GSNP Chair: Harald Pleiner, MPI Polymer Research Room: LACC 502B |
Tuesday, March 22, 2005 7:30PM - 8:06PM |
M5b.00001: Static and Dynamic Heterogeneities in Tetrahedratic Liquids Invited Speaker: The thermodynamic behavior of water and other tetrahedratic liquids such as silicon, silica, and carbon seems to be closely related to static heterogeneities. These static heterogeneities are related to the local structure of clusters of neighboring molecules and, when properly characterized, may offer an economical explanation of thermodynamic data. ``What matters'' most in determining some of the unusual properties of tetrahedratic liquids may be the fact that the local geometry of molecules and their neighbors is not spherical or oblong, but rather tetrahedral. With respect to static heterogeneities, this local geometry is critical. The dynamic behavior of tetrahedratic liquids seems to be closely related to dynamic heterogeneities, which seem to explain the dynamics of supercooled liquid water remarkably well. \newline \newline [1] Debenedetti, P. G. \& Stanley, H. E. 2003 The physics of supercooled and glassy water. {\it Physics Today\/} {\bf 56}[6], 40--46. [Preview Abstract] |
Tuesday, March 22, 2005 8:06PM - 8:42PM |
M5b.00002: Tetrahedral Order in Banana Liquid Crystals Invited Speaker: Bent-core liquid crystal molecules can exhibit phases that require a third-rank symmetric-traceless tensor order parameter, as well as a vector order parameter and the usual second-rank nematic order parameter. The combination gives rise to a rich variety of spatially homogeneous phases ranging from the well-known nematic to novel tetrahedratic and chiral liquids. I discuss experimental signatures of these phases and phase transitions between them.\\[0.3cm] L. Radzihovsky and T.C. Lubensky, Europhys. Lett.54, 206 (2001); Phys. Rev.E 66, 031704 (2002). [Preview Abstract] |
Tuesday, March 22, 2005 8:42PM - 9:18PM |
M5b.00003: Cross-coupling of Tetrahedratic Order Invited Speaker: We discuss how tetrahedratic order couples to external fields, forces and other variables [1-3]. In particular, we show that the application of an external electric field to a tetrahedratic phase induces quadrupolar orientational order, thus inducing a nematic phase in a field. We discuss a linear gradient term coupling tetrahedratic and quadrupolar order and show that this term could explain the ambidextrous chiral domains observed in nematic phases formed by achiral banana-shaped molecules. [1] H.R. Brand, H. Pleiner and P.E. Cladis, Eur. Phys. J. E7, 163 (2002). [2] P.E. Cladis, H. Pleiner and H.R. Brand, Eur.Phys. J E11, 283 (2003). [3] H.R. Brand, H. Pleiner and P.E. Cladis, Physica A, in print. [Preview Abstract] |
Tuesday, March 22, 2005 9:18PM - 9:54PM |
M5b.00004: Octupole moments in f-electron materials Invited Speaker: Multipole moments have recently been recognized as possible order parameters in solids. Unlike dipole moments, they are difficult to be detected experimentally, and may constitute hidden order parameters or fluctuations. By carefully designed experiments using X-ray scattering and magnetization under uniaxial stress, we now have evidence that magnetic octupoles are responsible for the unusual behavior found in certain solids such as Ce$_{0.75}$La$_{0.25}$B$_6$ and NpO$_2$. We clarify the basic idea of multipole physics, and present the current status of research. Ref: K. Kubo and Y. Kuramoto, J. Phys. Soc. Jpn. 72, 1859 (2003); ibid. 73, 216 (2004). [Preview Abstract] |
Tuesday, March 22, 2005 9:54PM - 10:30PM |
M5b.00005: Tetrahedratic Order in Biological Systems Invited Speaker: Time dependent braid and myelinic textures have been observed at the banana B7-isotropic transition. They are not observed in classical liquid crystals where there is only quadrupolar order. We discuss to what extent they are consistent with the coexistence of spatially dependent quadrupolar and tetrahedral order in a temperature gradient induced flow. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700