Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 3: Magnetic Semiconductors

MA 3.2: Vortrag

Montag, 25. Februar 2008, 10:30–10:45, H 1012

First-principles studies on dilute magnetic semiconductor based on ZnO — •Sanjeev Nayak¹, Alfred Hucht¹, Peter Entel¹, Masako Ogura², and Hisazumi Akai² — ¹Physics Department, University of Duisburg-Essen, Duisburg Campus, 47048 Duisburg, Germany — ²Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan

First-principles density functional theory is used to study the electronic properties of transition metal doped ZnO. Based on the experimental observation for low doping concentrations, only the substitutional doping of transition metal atoms in ZnO is considered. Our results shows spin-glass type of state for magnetic arrangement of Co spins as the lower energy state. Addition of on-site correlation energy in terms of Hubbard U, and the exchange coupling constants of cobalt spins suggest no long-range magnetic order in the diluted limit case. Our results can be compared to recent experiments, where no ferromagnetism has been observed in the system. Thus, this poses the questions whether ferromagnetism in the system can be from secondary phases?