Magnetism in graphene nanoislands
Magnetism in graphene nanoislands
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DOI：
10.1103/physrevlett.99.177204
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发表时间：
2007-10-26
影响因子：
8.6
通讯作者：
Palacios, J. J.
中科院分区：
文献类型：
--
作者：
Fernandez-Rossier, J.;Palacios, J. J.
我们研究了纳米尺寸的石墨烯结构与三角形和六边形的锯齿形边缘终止的磁性。我们讨论了岛的形状，属于两个石墨烯子晶格的原子数量的不平衡，零能态的存在，以及总磁矩和局部磁矩是如何密切相关的。我们认为电子相互作用的平均场近似的一个轨道的哈伯德模型和密度泛函计算。这两种描述产生的基态总自旋S值与Lieb的二分晶格定理相一致。三角形对于所有尺寸都具有有限的S，而六边形具有S = 0，并且在接近1.5 nm的临界尺寸以上产生局部矩。
We study the magnetic properties of nanometer-sized graphene structures with triangular and hexagonal shapes terminated by zigzag edges. We discuss how the shape of the island, the imbalance in the number of atoms belonging to the two graphene sublattices, the existence of zero-energy states, and the total and local magnetic moment are intimately related. We consider electronic interactions both in a mean-field approximation of the one-orbital Hubbard model and with density functional calculations. Both descriptions yield values for the ground state total spin S consistent with Lieb's theorem for bipartite lattices. Triangles have a finite S for all sizes whereas hexagons have S = 0 and develop local moments above a critical size of approximate to 1.5 nm.