Stability of the 1/3 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) - 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 vertical bar J(2)vertical bar 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 vertical bar J(2)vertical bar increases, the 1/3 plateau becomes more stable, exhibiting symmetric melting behavior. Specifically, for J(2) > 0, the Q = 0 up-up-down structure is stabilized, whereas for J(2) < 0, the root 3 x root 3 up-up-down structure is stabilized.