Electronic correlation and magnetism in multi-band Kondo lattice model [Elektronische Ressource] : application for disorder materials / von Vadym Bryksa

Electronic correlation and magnetism inmulti-band Kondo lattice modelApplication for disorder materialsDISSERTATIONzur Erlangung des akademischen GradesDr. Rer. Nat.im Fach Physikeingereicht an derMathematisch-Naturwissenschaftlichen Fakultät IHumboldt-Universität zu BerlinvonDipl.-Phys. Vadym Bryksa Ph.D.geboren am 01.01.1979 in Oleksandrija (Ukraine)Präsident der Humboldt-Universität zu Berlin:Prof. Dr. Christoph MarkschiesDekan der Mathematisch-Naturwissenschaftlichen Fakultät I:Prof. Dr. Lutz-Helmut SchönGutachter:1. Prof. Dr. W. Nolting2. Prof. Dr. W. Borgiel3. Prof. Dr. G. Tarasoveingereicht am: 31.03.2009Tag der mündlichen Prüfung: 23.10.2009AbstractWe propose a self-consistent approximate solution of the disorderedKondo-lattice model (KLM) to get the interconnected electronic andmagnetic properties of ’local-moment’ systems like diluted ferromag-netic semiconductors. Aiming at (A M ) compounds, where mag-1−x xnetic (M) and non-magnetic (A) atoms are distributed randomly over acrystal lattice, we present a theory which treats the subsystems of itin-erant charge carriers and localized magnetic moments in a homologousmanner. The coupling between the localizedts due to the itiner-ant electrons (holes) is treated by a modified RKKY-theory which mapsthe KLM onto an effective Heisenberg model. The disordered electronicand magnetic moment systems are both treated by coherent potentialapproximation (CPA) methods.