Kang J-S, Kim G, Wi S C, Lee S S, Choi S, Cho Sunglae, Han S W, Kim K H, Song H J, Shin H J, Sekiyama A, Kasai S, Suga S, Min B I
Department of Physics, The Catholic University of Korea, Puchon 420-743, Korea.
Phys Rev Lett. 2005 Apr 15;94(14):147202. doi: 10.1103/PhysRevLett.94.147202. Epub 2005 Apr 11.
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.
我们使用扫描光电子显微镜（SPEM）、X射线吸收光谱（XAS）和光电子能谱（PES）研究了潜在的稀磁半导体Ge0.94Mn0.06单晶的化学分布和局部电子结构。SPEM图像显示出条纹状微观结构，这是由富锰相和贫锰相之间的化学相分离产生的。锰2p XAS表明，富锰区域中的锰离子处于二价高自旋Mn2+状态，但它们不形成金属锰簇。锰3d PES光谱在低于费米能级（E(F)）约4 eV处有一个峰值，且在E(F)附近的光谱权重可忽略不计。该研究表明，在Ge1-xMnx中观察到的铁磁性源于相分离的富锰相。
