Stability of the 13 magnetization plateau of the J1−J2 kagome Heisenberg model

In this study, we investigate the finite-temperature properties of the spin-1/2 ${J}_{1}\ensuremath{-}{J}_{2}$ Heisenberg model on the kagome lattice using the orthogonalized finite-temperature Lanczos method. Under a zero magnetic field, the specific heat exhibits a double-peak structure, as $|{J}_{2}|$ increases. Additionally, at approximately ${J}_{2}=0$, the magnetic entropy remains finite, even at low temperatures. The finite-temperature magnetization curve reveals the asymmetric melting behavior of the 1/3 plateau around ${J}_{2}=0$. As $|{J}_{2}|$ increases, the 1/3 plateau becomes more stable, exhibiting symmetric melting behavior. Specifically, for ${J}_{2}>0$, the $\mathbf{Q}=\mathbf{0}$ up-up-down structure is stabilized, whereas for ${J}_{2}<0$, the $\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$ up-up-down structure is stabilized.