Fig. 4: Simulation of phase transition between HTP and LTP.
From: Organic radical ferroelectric crystals with martensitic phase transition
a Spin density plot of magnetic state. The local magnetic moments are from the O and N ions, while the neighboring N–O pairs are far from each other. b Relative free energy of HTP as a function of effective disorder (characterized by the state number N as mentioned before) under different temperatures. The color middle region: HTP owns a higher (lower) free energy than LTP at 267 K (399 K). The experimental N is just in this range. The free energy of LTP is taken as the base. c The simulated transition barriers between HTP to LTP with N = 5, at 399 K and 267 K, respectively. The barrier heights, defined from the top to the high free energy side are about 29.06 meV (399 K) and 21.84 meV (267 K), respectively.
