Possible impurity-induced ferromagnetism in II-GE-V2 chalcopyrite semiconductors
Possible impurity-induced ferromagnetism in II-GE-V2 chalcopyrite semiconductors
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DOI：
10.1103/physrevb.65.094415
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发表时间：
2002-02
影响因子：
3.7
通讯作者：
Yu-Jun Zhao;S. Picozzi;A. Continenza;W. Geng;A. Freeman
中科院分区：
文献类型：
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作者：
Yu-Jun Zhao;S. Picozzi;A. Continenza;W. Geng;A. Freeman
最近报道的室温铁磁（FM）半导体Cd 1 - x Mn x GeP 2 和Zn 1 - x Mn x GeP 2 表明II-IV-V 2 黄铜矿半导体在“自旋电子”研究中可能发挥重要作用。在这里，通过第一性原理密度泛函计算研究了 (i) Mn 掺杂 II-Ge-VI 2 (II=Zn 或 Cd 和 V=P 或 As) 黄铜矿的结构、电子和磁性特性以及 (ii) Cd 1 - x Mn x GeP 2 中 S 作为杂质的作用。我们发现对于 Mn 成分 x=0.25、0.50 和 1.0 的所有系统，反铁磁 (AFM) 态的总能量低于相应的 FM 态。这一预测与最近的实验结果一致，即 Zn 1 - x Mn x GeP 2 在 T 小于 47 K 时会经历 FM 到 AFM 相的转变。此外，由于 n 型 S 掺杂引入的电子，预计 Cd 1 - x Mn x GeP 2 中可能会发生向半金属 FM 相的转变，这表明载流子对于磁性半导体中 FM 耦合的重要性。正如预期的那样，当每个 S 替换 P 时，FM 相的总磁矩减少了 1 μB。
Recently reported room-temperature ferromagnetic (FM) semiconductors Cd 1 - x Mn x GeP 2 and Zn 1 - x Mn x GeP 2 point to a possible important role of II-IV-V 2 chalcopyrite semiconductors in "spintronic" studies. Here, structural, electronic, and magnetic properties of (i) Mn-doped II-Ge-VI 2 (II=Zn or Cd and V=P or As) chalcopyrites and (ii) the role of S as impurity in Cd 1 - x Mn x GeP 2 are studied by first-principles density functional calculations. We find that the total energy of the antiferromagnetic (AFM) state is lower than the corresponding FM state for all systems with Mn composition x=0.25, 0.50, and 1.0. This prediction is in agreement with a recent experimental finding that Zn 1 - x Mn x GeP 2 experiences a FM to AFM transition for T less than 47 K. Furthermore, a possible transition to the half-metallic FM phase is predicted in Cd 1 - x Mn x GeP 2 due to the electrons introduced by n-type S doping, which indicates the importance of carriers for FM coupling in magnetic semiconductors. As expected, the total magnetic moment for the FM phase is reduced by one μ B with each S substituting P.