Nematic and gas-liquid transitions for sticky rods on square and cubic lattices

Abstract

Using grand-canonical Monte Carlo simulations, we investigate the phase diagram of hard rods of length L with additional contact (sticky) attractions on square and cubic lattices. The phase diagram shows a competition between gas-liquid and ordering transitions (which are of demixing type on the square lattice for L ≥ 7 and of nematic type on the cubic lattice for L ≥ 5). On the square lattice, increasing attractions initially lead to a stabilization of the isotropic phase. On the cubic lattice, the nematic transition remains of weak first order upon increasing the attractions.In the vicinity of the gas-liquid transition, the coexistence gap of the nematic transition quickly widens. These features are different from nematic transitions in the continuum. * martin.oettel@uni-tuebingen.de 1 arXiv:1905.05501v2 [cond-mat.soft]

Interplay of orientational order and roughness in simulated thin film growth of anisotropically interacting particles

“…spherical particles with electric or magnetic multipole moments. The study of particles with anisotropic steric shapes * eelco.empting@uni-tuebingen.de has a long history in investigations of the behavior of liquid crystals 18,19 , while interaction anisotropy has been used to both study simple models of liquid crystals 20,21 and the assembly of magnetic nano-cubes 22 and to mimic effects of anisotropic substrates on film growth 23 . Growth with organic molecules in general means that both shape and interaction anisotropy are involved.…”

Alternative characterization of the nematic transition in deposition of rods on two-dimensional lattices

“…Other examples, corresponding to phase transitions in systems of hard particles of different shapes include triangles [2], squares [3][4][5][6][7][8][9], dimers [10][11][12][13], mixtures of squares and dimers [14,15], Y-shaped particles [16][17][18], tetrominoes [19,20], rods [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], rectangles [26,[37][38][39], disks [40,41], and hexagons [42]. Experimental realizations of such systems include tobacco mosaic virus [43,44], liquid crystals [45], f d virus [46][47][48], silica colloids [49,…”

“…Later, and based on the seminal work of Ghosh and Dhar 73 [21], several papers were devoted to the detailed study of 74 the transition occurring at intermediate density values in a 75 system of long straight rigid rods on 2D lattices with discrete 76 allowed orientations [22][23][24][25][26][27][28][29]. This transition was usually re-77 ferred to as isotropic to nematic (I-N) but due to the results 78 presented below the high coverage phase is also isotropic but 79 ordered, while the low-density isotropic phase is disordered.…”

“…In the just cited articles, it was shown that (1) the D-N phase transition belongs to the 2D Ising universality class for square lattices and the three-state Potts universality class for honeycomb and triangular lattices [22,23]; (2) the critical value of k which allows the formation of a nematic phase is k = 7 for square and triangular lattices [22,24] and k = 11 for honeycomb lattices [23]; (3) the critical density characterizing the D-N transition θ 1 follows a power law as θ 1 (k) ∝ k −1 [24][25][26]; and (4) the orientational order survives in a wide range of lateral interactions between the adsorbed k-mers [27][28][29].…”