Field-induced multiple order-by-disorder state selection in an antiferromagnetic honeycomb bilayer lattice

F. A. GÓMEZ ALBARRACÍN; H. D. ROSALES

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2016

1098-0121

In this paper we present a detailed study of the antiferromagnetic classical Heisenberg model on a bilayer honeycomb lattice in a highly frustrated regime in presence of a magnetic field. This study shows strong evidence of entropic order-by-disorder selection in different sectors of the magnetization curve. For antiferromagnetic couplings J1=Jx=Jp/3, we find that at low temperatures there are two different regions in the magnetization curve selected by this mechanism with different number of soft and zero modes. These regions present broken Z2 symmetry and are separated by a not fully collinear classical plateau at M=1/2. At higher temperatures, there is a crossover from the conventional paramagnet to a cooperative magnet. Finally, we also discuss the low temperature behavior of the system for a less frustrated region, J1=Jx < Jp/3.