The electronic structure of the new diluted magnetic semiconductor Ba 1−x K x (Zn 1−y Mn y) 2 As 2 (x = 0.30, y = 0.15) in single crystal form has been investigated by angle-resolved photoemission spectroscopy (ARPES). Measurements with soft x-rays clarify the host valence-band electronic structure primarily composed of the As 4p states. Two hole pockets around the Γ point, a hole corrugated cylinder surrounding the Γ and Z points, and an electron pocket around the Z point are observed, and explain the metallic transport of Ba 1−x K x (Zn 1−y Mn y) 2 As 2. This is contrasted with Ga 1−x Mn x As (GaMnAs), where it is located above the As 4p valence-band maximum (VBM) and no Fermi surfaces have been clearly identified. Resonance soft x-ray ARPES measurements reveal a nondispersive (Kondo resonance-like) Mn 3d impurity band near the Fermi level, as in the case of GaMnAs. However, the impurity band is located well below the VBM, unlike the impurity band in GaMnAs, which is located around and above the VBM. We conclude that, while the strong hybridization between the Mn 3d and the As 4p orbitals plays an important role in creating the impurity band and inducing high temperature ferromagnetism in both systems, the metallic transport may predominantly occur in the host valence band in Ba 1−x K x (Zn 1−y Mn y) 2 As 2 and in the impurity band in GaMnAs.

Here we report the successful synthesis of a spin-& charge-decoupled diluted magnetic semiconductor (Ca,Na)(Zn,Mn) 2 As 2 , crystallizing into the hexagonal CaAl 2 Si 2 structure. The compound shows a ferromagnetic transition with a Curie temperature up to 33 K with 10% Na doping, which gives rise to carrier density of n p~1 0 20 cm -3 . The new DMS is a soft magnetic material with H C <400 Oe. The anomalous Hall effect is observed below the ferromagnetic ordering temperature.With increasing Mn doping, ferromagnetic order is accompanied by an interaction between the local spin and mobile charge, giving rise to a minimum in resistivity at low temperatures and localizing the conduction electrons. The system provides an ideal platform for studying the interaction of the local spins and conduction electrons. PACS number(s): 75.50. Pp, 75.30.Kz, 76.75.+i 2 Diluted magnetic semiconductors (DMS) have received much attention due to their potential for application in the field of spintronics [1][2][3][4][5] . In typical III-V DMS systems, such as (Ga,Mn)As, (In,Mn)As and (Ga,Mn)N, substitution of divalent Mn atoms into trivalent Ga or In sites leads to severely limited chemical solubility, resulting in metastable specimens only available as epitaxial thin films. Moreover, the hetero-valence substitution, which simultaneously dopes both charge and spin, makes it difficult to individually control each quantum degree of freedom.Recently, a new type of DMS, Li(Zn,Mn)As (termed "111" following the three chemical composition ratios), was discovered by Deng et al, The "122" DMS (Ba,K)(Zn,Mn) 2 As 2 shares the tetragonal ThCr 2 Si 2 structure with the "122" iron pnictide superconductor (Ba,K)Fe 2 As 2 and the antiferromagnet BaMn 2 As 2 9 , each with a lattice mismatch of less than 2%, giving rise to the unprecedented possibility of designing various interface-based devices among DMS, superconductors and magnets. Moreover, an increase in the carrier density could enhance the Curie temperature further to 230K in this 122 system. 10The idea of decoupling spin and charge has since been extended, resulting in the discovery of two 3 additional DMS system, "111" type Li(Zn,Mn)P 11 and "1111" types (La,Ca)(Zn,Mn)SbO & (La,Ca)(Zn,Mn)AsO 12,13 Depending on the composition, "122" compounds can crystallize into the tetragonal ThCr 2 Si 2 structure, as in the case of (Ba,K)(Zn,Mn) 2 As 2 , or the hexagonal CaAl 2 Si 2 structure. Interestingly, the hexagonal compounds CaMn 2 As 2 and CaMn 2 Sb 2 are fully frustrated classical magnetic systems with a honeycomb lattice of Mn atoms, exhibiting a complex magnetic phase diagram. 14 Here we report the synthesis of bulk specimens of a new DMS (Ca,Na)(Zn,Mn) 2 As 2 with the hexagonal CaAl 2 Si 2 structure, as shown in Fig. 1(a). ExperimentalPolycrystalline samples of (Ca,Na)(Zn,Mn) 2 As 2 were synthesized via the solid-state reaction method. The synthesis of starting materials CaAs and Na 3 As was described in an earlier paper. 8These starting materials were mixed with high-purity Zn, M...