Magneto-optical spectra and the presence of an impurity band in p-type ferromagnetic semiconductor (Ga,Fe)Sb with high Curie temperature
Magneto-optical spectra and the presence of an impurity band in p-type ferromagnetic semiconductor (Ga,Fe)Sb with high Curie temperature
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DOI：
10.1063/1.5083175
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发表时间：
2019-02
期刊：
影响因子：
6.1
通讯作者：
Karumuri Sriharsha;L. D. Anh;N. Tu;Shobhit Goel;Masaaki Tanaka
中科院分区：
文献类型：
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作者：
Karumuri Sriharsha;L. D. Anh;N. Tu;Shobhit Goel;Masaaki Tanaka
利用磁性圆二色性（MCD）光谱，在可见光区（1.5-5 eV）和红外光区（0.6-1.7 eV）系统地研究了低温分子束外延生长的p型铁磁半导体（Ga 1 −x，Fex）Sb的能带结构。我们观察到两个峰的红外MCD光谱，可以解释的光学跃迁有关的费米能级（EF）位于铁相关的杂质带（IB）的带隙。随着x的增加，两个峰的能量移动表明，铁相关的IB延伸到带隙和EF相应地上升。此外，在这些（Ga，Fe）Sb薄膜中的空穴载流子的迁移率估计由霍尔测量是非常低的（0.2-2厘米2/Vs），这是一致的，我们的结论，即空穴载流子和EF驻留在IB，而不是在价带。我们的研究结果提供了深入了解p型铁磁半导体（Ga，Fe）Sb的能带结构与高居里温度，这是有希望实现自旋电子器件在室温下工作。
By using magnetic circular dichroism (MCD) spectroscopy with photon energy in both visible (1.5–5 eV) and infrared light regions (0.6–1.7 eV), we systematically investigate the band structure of p-type ferromagnetic semiconductor (Ga1−x,Fex)Sb with various Fe concentrations x = 2%–20% grown by low-temperature molecular beam epitaxy. We observed two peaks in the infrared MCD spectra that can be explained by the optical transitions related to the Fermi level (EF) located in an Fe-related impurity band (IB) in the bandgap. As x increases, the energy shifts of the two peaks suggest that the Fe-related IB extends into the bandgap and EF rises correspondingly. Furthermore, the mobility of hole carriers in these (Ga,Fe)Sb thin films estimated by Hall measurements is very low (0.2–2 cm2/Vs), which is consistent with our conclusion that the hole carriers and EF reside in the IB rather than in the valence band. Our results provide insights into the band structure of p-type ferromagnetic semiconductors (Ga,Fe)Sb with high Curie temperature, which is promising for the realization of spintronic devices operating at room temperature.