The joint effect of elasticity, interaction energy and entropy on behavior of pressure- and temperature-induced electronic bistability in a family of two-dimensional Hofman-like coordination polymers

A comprehensive study of temperature- and pressure-induced spin transition and a change in the physical properties of 2D Hofmann-type compounds [Fe(Fpz)(2)M(CN)(4)] (M = Pd, Ni; Fpz = F-pyrazine) was carried out. A huge change in the magnetic, vibrational, optical, and elastic properties during spin transition under pressure has been induced. The abnormal behavior of the transition temperature and hysteresis has been observed for [Fe(Fpz)(2)Pd(CN)(4)]. In the paramagnetic [Fe(Fpz)(2)Ni(CN)(4)] compound, the spin transition has been induced by pressure. The combination of the elastic interaction and Monte Carlo models allowed us to establish a synergy effect of elastic and interaction energies as well as entropy for the formation of a variety of properties of compounds during the spin transition. The pressure-induced spin transition of the referred compounds has been studied and their behavior under pressure was analyzed at the atomic level.