Prediction of the existence of a spin-liquid-like phase in the antiferromagnetic ${J}_{1}\text{\ensuremath{-}}{J}_{2} \text{spin-}\frac{1}{2}$ system on the body-centered cubic lattice

Prediction of the existence of a spin-liquid-like phase in the antiferromagnetic $J_{1} − J_{2} spin- \frac{1}{2}$ system on the body-centered cubic lattice

E. Jurčišinová and M. Jurčišin

Phys. Rev. B 101, 214443 – Published 29 June 2020

Abstract

The phase transitions and thermodynamics of the antiferromagnetic system with the presence of the next-to-nearest-neighbor interaction on the body-centered cubic lattice are studied within an exactly solvable model using the recursive lattice approach. It is shown that, besides the Néel and collinear antiferromagnetic phases and the paramagnetic phase discussed in the literature, the model clearly exhibits the existence of an intermediate phase that separates the antiferromagnetic phases. This new phase is observed in a narrow interval of the frustration parameter for nonzero temperatures and is realized in the form of a discrete (single-point-like) ground state in the zero-temperature limit. Transitions between all model phases are studied and it is shown that all transitions between each antiferromagnetic phase of the model and the paramagnetic one as well as between the antiferromagnetic phases and the intermediate phase have the second-order phase transition nature. The magnetization, entropy, and specific heat capacity properties of all phases of the model are studied in detail. Three different ground states are identified and their macroscopic degeneracies are determined. The anomalous Schottky-type behavior of the specific heat capacity in the vicinity of the highly macroscopically degenerated ground state realized for exactly given value of the frustration parameter is observed and discussed. Besides, the existence of the intermediate phase leads to the nontrivial temperature behavior of the specific heat capacity where, in addition to the Schottky-type anomaly related to the frustration, three discontinuous jumps related to the three consecutive second-order phase transitions between corresponding model phases are observed.