title: Biaxial nematic phase in the Maier-Saupe model for a mixture of discs and cylinders.
abstract: We analyze the global phase diagram of a Maier-Saupe lattice model with the inclusion of shape-disordered degrees of freedom to mimic a mixture of oblate and prolate molecules (discs and cylinders). In the neighborhood of a Landau multicritical point, solutions of the statistical problem can be written as a Landau-de Gennes expansion for the free energy. If the shape-disordered degrees of freedom are quenched, we confirm the existence of a biaxial nematic structure. If orientational and disorder degrees of freedom are allowed to thermalize, this biaxial solution becomes thermodynamically unstable. Also, we use a two-temperature formalism to mimic the presence of two distinct relaxation times, and show that a slight departure from complete thermalization is enough to stabilize a biaxial nematic phase.
authors.affiliation: Instituto de Física, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: E F
authors.initials: EF
authors.lastname: Henriques
authors.forename: S R
authors.initials: SR
authors.lastname: Salinas
mesh_terms: D000465:Algorithms; D050866:Liquid Crystals; D015233:Models, Statistical; D044367:Phase Transition; D010825:Physics / Q000379:methods*; D012996:Solutions; D013696:Temperature; D013816:Thermodynamics
chemical_list: D012996:Solutions