Spin-Peierls transition in low-dimensional quantum spin systems: a Green’s function approach
Abstract
We study the spin-Peierls (SP) transition of one-dimensional chain polymeric complexes coupled to lattice by means of many-body Green’s function theory. The chain effective elastic constant is an intrinsic factor that determines the order of SP transition. It is found that the SP transition temperature TSP and the susceptibility-maximum temperature Tmax are in agreement with the experimental results. When an external magnetic field is applied to the chain, it makes TSP and Tmax decrease, and drives the SP transition from the second order to the first order. Besides, we show that the two-site thermal entanglement entropy is a good