2011/05/31 by Moisés Rojas, M. Rojas, Onofre Rojas +1
Physics and Astronomy · #Condensed matter physics #Ferrimagnetism #Ferromagnetism #Ground state #Ising model #Magnetic field #Magnetization #Opinion Dynamics and Social Influence #Phase (matter) #Phase diagram #Phase transition #Physics #Quantum many-body systems #Quantum mechanics #Theoretical and Computational Physics #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.86.051116
published as Phys. Rev. E 86, 051116 (2012) · 12 pages and 18 figures
openalex publication_date 2012/11/16 · arxiv created 2012/11/26 · arxiv updated 2015/03/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Through the direct decoration transformation approach, we obtain a general solution for the pentagonal Ising model, showing its equivalence to the isotropic free-fermion eight-vertex model. We study the ground-state phase diagram, in which one ferromagnetic (FM) state, one ferrimagnetic (FIM) state, and one frustrated state are found. Using the exact solution of the pentagonal Ising model, we discuss the finite-temperature phase diagrams and find a phase transition between the FIM state and the disordered state as well as a phase transition between the disordered state and the FM state. We also discuss some additional remarkable properties of the model, such as the magnetization, entropy, and specific heat, at finite temperature and at its low-temperature asymptotic limit. Because of the influence of the second-order phase transition between the frustrated and ferromagnetic phases, we obtain surprisingly low values of the entropy and the specific heat until the critical temperature is reached.