Thermal Entanglement in Spin-Dimer <i>V</i> ⁴⁺ with a Strong Magnetic Field

Abstract

We study the entanglement in Heisenberg dimer single molecular magnets V4+ with a strong magnetic field by means of the measure of entanglement called ``concurrence'' and find that thermal entanglement exists for both the ferromagnetic (FM) and antiferromagnetic (AFM) cases. In the FM case, entanglement vanishes for anisotropic parameter λ = 0 while in the AFM case, entanglement exits in the whole region of anisotropic parameter 0⩽λ⩽1. Entanglement variations with anisotropic parameter λ, magnetic field B and temperature T are evaluated. We find a critical magnetic field at which the concurrence changes sharply from zero to maximum entanglement.