title: Spatial chemical inhomogeneity and local electronic structure of Mn-doped Ge ferromagnetic semiconductors.
abstract: We have investigated the chemical distributions and the local electronic structure of potential diluted magnetic semiconductor Ge0.94Mn0.06 single crystals using scanning photoelectron microscopy (SPEM), x-ray absorption spectroscopy (XAS), and photoemission spectroscopy (PES). The SPEM image shows the stripe-shaped microstructures, which arise from the chemical phase separation between the Mn-rich and Mn-depleted phases. The Mn 2p XAS shows that the Mn ions in the Mn-rich region are in the divalent high-spin Mn2+ states but that they do not form metallic Mn clusters. The Mn 3d PES spectrum exhibits a peak centered at approximately 4 eV below E(F) and the negligible spectral weight near E(F). This study suggests that the observed ferromagnetism in Ge1-xMnx arises from the phase-separated Mn-rich phase.
authors.affiliation: Department of Physics, The Catholic University of Korea, Puchon 420-743, Korea.
authors.forename: J-S
authors.initials: JS
authors.lastname: Kang
authors.forename: G
authors.initials: G
authors.lastname: Kim
authors.forename: S C
authors.initials: SC
authors.lastname: Wi
authors.forename: S S
authors.initials: SS
authors.lastname: Lee
authors.forename: S
authors.initials: S
authors.lastname: Choi
authors.forename: Sunglae
authors.initials: S
authors.lastname: Cho
authors.forename: S W
authors.initials: SW
authors.lastname: Han
authors.forename: K H
authors.initials: KH
authors.lastname: Kim
authors.forename: H J
authors.initials: HJ
authors.lastname: Song
authors.forename: H J
authors.initials: HJ
authors.lastname: Shin
authors.forename: A
authors.initials: A
authors.lastname: Sekiyama
authors.forename: S
authors.initials: S
authors.lastname: Kasai
authors.forename: S
authors.initials: S
authors.lastname: Suga
authors.forename: B I
authors.initials: BI
authors.lastname: Min