Antiferromagnetic triangular BlumeCapel model with hardcore exclusions
Abstract
Using Monte Carlo simulation, we analyze phase transitions of two antiferromagnetic (AFM) triangular BlumeCapel (BC) models with AFM interactions between thirdnearest neighbors. One model has hardcore exclusions between the nearestneighbor (1NN) particles (3NN1 model) and the other has them between the nearestneighbor and nextnearestneighbor particles (3NN12 model). Finitesize scaling analysis reveals that in these models, the transition from the paramagnetic to longrange order (LRO) AFM phase is either of the first order or goes through an intermediate phase which might be attributed to the BerezinskiiKosterlitzThouless (BKT) type. The properties of the lowtemperature phase transition to the AFM phase of the 1NN, 3NN1, and 3NN12 models are found to be very similar for almost all values of a normalized singleion anisotropy parameter, 0<δ<1.5. Higher temperature behavior of the 3NN12 and 3NN1 models is rather different from that of the 1NN model. Three phase transitions are observed for the 3NN12 model: from the paramagnetic phase to the phase with domains of the LRO AFM phase at T_{c}, from this structure to the diluted frustrated BKTtype phase at T_{2}, and from the frustrated phase to the AFM LRO phase at T_{1}. For the 3NN12 model, T_{c}>T_{2}>T_{1} at 0<δ<1.15 (range I), T_{c}≈T_{2}>T_{1} at 1.15<δ<1.3 (range II), and T_{c}=T_{2}=T_{1} at 1.3<δ<1.5 (range III). For the 3NN1 model, T_{c}≈T_{2}>T_{1} at 0<δ<1.2 (range II) and T_{c}=T_{2}=T_{1} at 1.2<δ<1.5 (range III). There is only one firstorder phase transition in range III. The transition at T_{c} is of the first order in range II and either of a weak first order or a second order in range I.
 Publication:

Physical Review E
 Pub Date:
 May 2014
 DOI:
 10.1103/PhysRevE.89.052144
 arXiv:
 arXiv:1403.1492
 Bibcode:
 2014PhRvE..89e2144I
 Keywords:

 64.60.Ht;
 Dynamic critical phenomena;
 Condensed Matter  Statistical Mechanics
 EPrint:
 12 pages, 15 figures, submitted for publication