Interplay between the magnetic and transport properties in the III-V diluted magnetic semiconductor Ga1-xMnxAs
Interplay between the magnetic and transport properties in the III-V diluted magnetic semiconductor Ga1-xMnxAs
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DOI：
10.1103/physrevb.56.13103
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发表时间：
1997-11-15
影响因子：
3.7
通讯作者：
Borghs, G
中科院分区：
文献类型：
--
作者：
VanEsch, A;VanBockstal, L;Borghs, G
使用低温分子束外延生长程序，ga1 - xmnxas - III-V稀释磁性半导体- Mn浓度高达x接近9%。在临界温度T-c下（x=0.03-0.05时T-c约为50 K）， Mn-h配合物之间的相互作用导致顺磁性向铁磁性相变发生。这些化合物中的空穴输运受到空穴与Mn三维自旋之间的反铁磁交换相互作用的强烈影响。给出了在Tc（）以上和以下的输运行为模型。在T-c以上，所有材料都表现出输运行为，这是金属-绝缘体过渡附近系统的特征。在T-c以下，由于自发磁化强度的上升，自旋无序散射减小，费米能级对迁移率边缘的相对位置发生变化。当磁化强度达到饱和值（低于10 K）时，变程跳变是主要的传导机制。负磁阻是空穴波函数在外加磁场中膨胀的结果。
Using a low-temperature molecular-beam epitaxy growth procedure, Ga1-xMnxAs-a III-V diluted magnetic semiconductor-is obtained with Mn concentrations up to x similar to 9%. At a critical temperature T-c (T-c approximate to 50 K for x=0.03-0.05), a paramagnetic to ferromagnetic phase transition occurs as the result of the interaction between Mn-h complexes. Hole transport in these compounds is strongly affected by the antiferromagnetic exchange interaction between holes and Mn 3d spins. A model for the transport behavior both above and below Tc( )is given. Above T-c, all materials exhibit transport behavior which is characteristic for systems near the metal-insulator transition. Below T-c, due to the rising spontaneous magnetization, spin-disorder scattering decreases and the relative position of the Fermi level towards the mobility edge changes. When the magnetization has reached its saturation value (below similar to 10 K) variable-range hopping is the main conduction mechanism. The negative magnetoresistance is the result of the expansion of the hole wave functions in an applied magnetic field.