Modeling of the gate-controlled Kondo effect at carbon point defects in graphene
Modeling of the gate-controlled Kondo effect at carbon point defects in graphene
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DOI：
10.1103/physrevb.97.155419
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发表时间：
2018-04-18
影响因子：
3.7
通讯作者：
Anders, Frithjof B.
中科院分区：
文献类型：
--
作者：
May, Daniel;Lo, Po-Wei;Anders, Frithjof B.
我们研究了单层石墨烯中单个碳缺陷附近的磁性。我们在一个有效的双轨道单杂质模型中包含了未束缚的σ轨道和空位诱导的束缚π态。局部磁矩稳定的库仑相互作用，以及一个显着的铁磁Hund的规则之间的轨道耦合的密度泛函理论计算预测。轨道和狄拉克费米子之间的杂化由空位附近的石墨烯片的曲率产生。我们目前的结果使用威尔逊的数值重整化群方法计算的局部光谱函数的一个现实的石墨烯能带结构，并找到三个不同的制度，根据填充，控制化学势，和杂交强度。这些不同区域的特征在于不同的磁性。计算的光谱函数定性同意最近的扫描隧道光谱石墨烯空位。
We study the magnetic properties in the vicinity of a single carbon defect in a monolayer of graphene. We include the unbound sigma orbital and the vacancy-induced bound pi state in an effective two-orbital single-impurity model. The local magnetic moments are stabilized by the Coulomb interaction as well as a significant ferromagnetic Hund's rule coupling between the orbitals predicted by a density functional theory calculation. A hybridization between the orbitals and the Dirac fermions is generated by the curvature of the graphene sheet in the vicinity of the vacancy. We present results for the local spectral function calculated using Wilson's numerical renormalization group approach for a realistic graphene band structure and find three different regimes depending on the filling, the controlling chemical potential, and the hybridization strength. These different regions are characterized by different magnetic properties. The calculated spectral functions qualitatively agree with recent scanning tunneling spectra on graphene vacancies.