Electric-field-induced isotropic-nematic phase transition.

Abstract

We measure optically the quadrupolar order S induced by a stabilizing electric field E in the isotropic phase of the nematogenic 4'-n-pentyl-4-cyanobiphenyl, with large positive dielectric anisotropy ${\mathrm{\ensuremath{\epsilon}}}_{\mathit{a}}$\ensuremath{\sim}10. For high enough field and low enough temperature, a paranematic-nematic first-order transition is induced, with a critical point at ${\mathit{E}}_{\mathit{c}}$=1.41\ifmmode\times\else\texttimes\fi{}${10}^{5}$ V/cm, ${\mathit{T}}_{\mathit{c}}$=${\mathit{T}}_{\mathit{N}\mathit{I}}$+0.65 K, and ${\mathit{S}}_{\mathit{c}}$=0.15, where ${\mathit{T}}_{\mathit{N}\mathit{I}}$ is the nematic-isotropic phase-transition temperature.