论文标题
用两个带电空缺的石墨烯量子点的电子和磁性
Electronic and magnetic properties of graphene quantum dots with two charged vacancies
论文作者
论文摘要
使用平均田间哈伯德模型研究了六角形石墨烯量子点的两个带电空缺的系统的电子和磁性，这是电荷杂质的库仑电势强度$β$的函数。对于$β= 0 $，空缺的磁性由Lieb的规则决定，在该规则中，相反的（相同）亚晶状体空位是通过抗磁性耦合的（铁磁性上）和表现出Fermi振荡的。在这里，我们证明了亚临界区域内非磁性方案的出现：由于库仑的潜在强度增加到$β\ sim 0.1 $，然后才达到沮丧的原子倒塌状态，因此磁化强烈抑制了磁化磁化；地面状态的总旋转由$ s_ {z {z} = 0 $ co n $ for tos sublattions Conformations和相同的sublattications配置。当远程电子 - 电子插入包括在扩展的平均田间哈伯德模型中时，挫折崩溃的临界值从$β_{cf} \ sim 0.28 $增加到$β_{cf} \ sim 0.36 $ 0.36 $ for $ r <27 \ 27 \Å$。
Electronic and magnetic properties of a system of two charged vacancies in hexagonal shaped graphene quantum dots are investigated using a mean-field Hubbard model as a function of the Coulomb potential strength $β$ of the charge impurities and the distance R between them. For $β=0$, the magnetic properties of the vacancies are dictated by Lieb's rules where the opposite (same) sub-lattice vacancies are coupled antiferromagnetically (ferromagnetically) and exhibit Fermi oscillations. Here, we demonstrate the emergence of a non-magnetic regime within the subcritical region: as the Coulomb potential strength is increased to $β\sim 0.1$ , before reaching the frustrated atomic collapse regime, the magnetization is strongly suppressed and the ground state total spin is given by $S_{z}=0$ both for opposite and same sublattice vacancy configurations. When long-range electron-electronz in-teractions are included within extended mean-field Hubbard model, the critical value for the frustrated collapse increases from $β_{cf} \sim 0.28$ to $β_{cf} \sim 0.36$ for $R < 27 \ Å $ .
