Electronic transport through a graphene-based ferromagnetic/normal/ferromagnetic junction
Electronic transport through a graphene-based ferromagnetic/normal/ferromagnetic junction
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DOI：
10.1088/0953-8984/22/3/035301
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发表时间：
2010-01
期刊：
影响因子：
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通讯作者：
Jiang-chai Chen;Shu-guang Cheng;S. Shen;Qing Sun
中科院分区：
文献类型：
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作者：
Jiang-chai Chen;Shu-guang Cheng;S. Shen;Qing Sun
利用Landauer-Büttiker方法和非平衡绿色函数技术研究了石墨烯基铁磁/正常/铁磁结中的电子输运.结果表明，对于锯齿形边缘的情况，平行结构的导磁总是大于e ~ 2/h，而对于反平行结构，导磁由于带选择规则而变为零。因此，当费米能位于狄拉克点附近时，磁阻（MR）平台值为100%。此外，选择较窄的石墨烯带可以产生较宽的100%MR平台，并且中心石墨烯区域的长度变化不影响100%MR平台。尽管无序会降低MR平台，但即使在大无序强度的情况下，平台值仍然可以保持约50%。此外，当左右引线的磁化具有相对角度时，电导作为角度的余弦函数而变化。更重要的是，对于扶手椅边缘的情况下，MR通常是小的。因此，更有利的是通过使用锯齿形边缘石墨烯带来制造石墨烯基自旋阀器件。
Electronic transport in a graphene-based ferromagnetic/normal/ferromagnetic junction is investigated by means of the Landauer–Büttiker formalism and the nonequilibrium Green function technique. For the zigzag edge case, the results show that the conductance is always larger than e2/h for the parallel configuration of lead magnetizations, but for the antiparallel configuration the conductance becomes zero because of the band-selective rule. Therefore, a magnetoresistance (MR) plateau emerges with the value 100% when the Fermi energy is located around the Dirac point. In addition, choosing narrower graphene ribbons can yield wider 100% MR plateaus and the length change of the central graphene region does not affect the 100% MR plateaus. Although the disorder will reduce the MR plateau, the plateau value can still be kept about 50% even in a large disorder strength case. In addition, when the magnetizations of the left and right leads have a relative angle, the conductance changes as a cosine function of the angle. What is more, for the armchair edge case, the MR is usually small. So, it is more favorable to fabricate a graphene-based spin valve device by using a zigzag edge graphene ribbon.