title: Ruderman-Kittel-Kasuya-Yosida-like ferromagnetism in MnxGe1-x.
abstract: The nature and origin of ferromagnetism in magnetic semiconductors is investigated by means of highly precise electronic and magnetic property calculations on MnxGe1-x as a function of the location of Mn sites in a large supercell. Surprisingly, the coupling is not always ferromagnetic (FM), even for large Mn-Mn distances. The exchange interaction between Mn ions oscillates as a function of the distance between them and obeys the Ruderman-Kittel-Kasuya-Yosida analytic formula. The estimated Curie temperature is in good agreement with recent experiments, and the estimated effective magnetic moment is about 1.7mu(B)/Mn, in excellent agreement with the experimental values, (1.4-1.9)mu(B)/Mn.
authors.affiliation: Department of Physics & Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Yu-Jun
authors.initials: YJ
authors.lastname: Zhao
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shishidou
authors.forename: A J
authors.initials: AJ
authors.lastname: Freeman