Low-temperature magnetoresistance (MR) in the variable-range hopping (VRH) regime of undoped AlxIn1?xSb/InSb quantum wells was studied. The low-T resistance shows that the two dimensional (2D) Mott VRH crossovers to Efros-Shklovskii (ES) VRH due to the Coulomb interaction with lowering T. The anisotropic negative MR in weak magnetic fields was explained by the quantum interference in the VRH. The in-plane positive MR in higher fields found in ES VRH regime was attributed to the spin-Zeeman effect that suppresses the hops between singly occupied states in the presence of intra-state correlation. As for the orbital MR subtracted from perpendicular MR, in deeply insulating regime the negative MR saturates above a characteristic field followed by an exponential increase of the positive MR in agreement with the quantum interference and the subsequent shrinkage of wave functions with increasing field, while in barely insulating regime of the 2D metal-insulator (MI) transition a large negative MR inexplicable survives even in the extremely high magnetic-fields.
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机译：研究了低温磁阻（MR）在未掺杂的Alxin1的可变范围跳跃（VRH）制度中。研究了XSB / INSB量子孔。低T电阻表明，由于与降低T的库仑相互作用，二维（2D）Mott VRH交叉效应为efros-shklovskii（ES）VRH。通过VRH的量子干扰解释了弱磁场中的各向异性负MR.的各向异性负极MR 。 ES VRH制度中发现的更高领域的面内阳性MR归因于旋转塞曼效应，其在存在局内相关性存在下抑制单独占用的状态之间的跃点。对于从垂直MR中减去的轨道MR，在深度绝缘的方案中，负MR饱和在特征领域之上，然后与量子干扰的正MR的指数增加，以及随后的波函数随着越来越多的领域的收缩。即使在极高的磁场中，2D金属 - 绝缘体（MI）过渡的大型金属绝缘体（MI）的绝缘制度也莫名其妙的生存。
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