Nematic-Isotropic Transition & Landau Theory

Liquid crystals undergo a weakly first-order transition between the isotropic phase (random orientations) and the nematic phase (aligned rods). The Landau free energy F(S) = a(T)S² − bS³ + cS⁴ captures the discontinuous jump in order parameter S at T_NI, driven by the cubic term which forbids a continuous transition.

Parameters

Temperature T: 0.00 (relative to T*) Coupling b: 1.00 Rods N: 80 Noise: 0.10

Order parameter S: —
Phase: —

F(S) = a(T)S² − bS³ + cS⁴
a(T) = (T−T*)/T*, b=cubic, c=1
First-order: jump at T_NI > T*