2005/01/31 by D. R. Neuber, Danilo R. Neuber, M. Daghofer +6
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Coulomb #Density matrix renormalization group #Electron #Ferromagnetism #Magnetic and transport properties of perovskites and related materials #Phase (matter) #Phase diagram #Physics #Polaron #Quantum #Quantum mechanics #Rare-earth and actinide compounds #Spins #Superexchange #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.73.014401
published as Phys. Rev. B 73, 014401 (2006) · 7 pages, 10 figures; final version to appear in Phys. Rev. B
arxiv created 2005/12/02 · openalex publication_date 2006/01/03 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We present an extensive numerical study of the ferromagnetic Kondo lattice model with quantum mechanical S=3∕2 core spins. We treat one orbital per site in one dimension using the density-matrix renormalization group and include on-site Coulomb repulsion between the electrons. We examine parameters relevant to manganites, treating the range of low to intermediate doping, 0\ensuremath\lesssimx<0.5. In particular, we investigate whether quantum fluctuations favor phase separation over the ferromagnetic polarons observed in a model with classical core spins. We obtain very good agreement of the quantum model with previous results for the classical model, finding separated polarons, which are repulsive at short distance for finite t2g superexchange J^\ensuremath'. Taking on-site Coulomb repulsion into account, we observe phase separation for small but finite superexchange J^\ensuremath', whereas for larger J^\ensuremath', polarons are favored in accordance with simple energy considerations previously applied to classical spins. We discuss the interpretation of compressibilities and present a phase diagram with respect to doping and the t2g superexchange parameter J^\ensuremath' with and without Coulomb repulsion.