2004/10/31 by Carsten Timm, Ulrich Schollwöck · 2 citations
Materials Science · Physics and Astronomy · #Magnetism in coordination complexes #Organic and Molecular Conductors Research #Quantum and electron transport phenomena #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevb.71.224414
published as Phys. Rev. B 71, 224414 (2005) · 8 pages RevTeX, 8 figures included
openalex publication_date 2005/06/21 · arxiv created 2005/06/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Spin-crossover molecules having a low-spin ground state and a low-lying excited high-spin state are promising components for molecular electronics. We theoretically examine one-dimensional spin-crossover chain molecules of the type of Fe2+ triazole complexes. The existence of the additional low-spin/high-spin degree of freedom leads to rich behavior already in the ground state. We obtain the complete ground-state phase diagram, taking into account an elastic nearest-neighbor interaction, a ferromagnetic or antiferromagnetic exchange interaction between the magnetic ions, and an external magnetic field. Ground-state energies are calculated with high numerical precision using the density-matrix renormalization group. Besides pure low-spin, high-spin, and alternating low-spin/high-spin phases we obtain a number of periodic ground states with longer periods, which we discuss in detail. For example, for antiferromagnetic coupling there exists a dimer phase with a magnetic unit cell containing two high-spin ions forming a spin singlet and a single low-spin ion, which is stabilized by the energy gain for singlet formation.