Multi-orbital Anderson models and the Kondo effect: a NCA study enhanced by vertex corrections

Autor:	Sebastian O. Schmitt, Norbert Grewe, Torben Jabben
Rok vydání:	2009
Předmět:	Physics Solid-state physics Condensed matter physics Complex system Electron Condensed Matter Physics Spectral line Electronic Optical and Magnetic Materials Impurity Quantum mechanics Condensed Matter::Strongly Correlated Electrons Strongly correlated material Kondo effect Anderson impurity model
Zdroj:	The European Physical Journal B. 68:23-32
ISSN:	1434-6036 1434-6028
DOI:	10.1140/epjb/e2009-00064-0
Popis:	The low energy region of certain transition metal compounds reveals dramatic correlation effects between electrons, which can be studied by photoelectron spectroscopy. Theoretical investigations are often based on multi-orbital impurity models, which exhibit modified versions of the Kondo effect. We present a systematic study of a multi-orbital Anderson-like model, based on a new semi-analytical impurity solver which goes beyond simple modifications of the well known NCA. We discuss one-particle excitation spectra and in particular the role of level positions and Coulomb-matrix elements. It is shown that the low-energy region as well as the overall features of spectra critically depend on the model parameters and on the quality of the approximations used. Recent photoelectron experiments and corresponding existing calculations are put into perspective. An interesting crossover scenario between different regimes of ground states with characteristically different local correlations is uncovered.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::691849ee80b794575575d81eefd37f31 https://doi.org/10.1140/epjb/e2009-00064-0 Zobrazit plný text záznamu Plný text ve formátu PDF