Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
J Chem Phys. 2010 Dec 14;133(22):224705. doi: 10.1063/1.3511782.
We investigated the effects of periodic external potentials on properties of charge carriers in graphene using both the first-principles method based on density functional theory (DFT) and a theoretical approach based on a generalized effective spinor Hamiltonian. DFT calculations were done in a modified Kohn-Sham procedure that includes the effects of the periodic external potential. Unexpected energy band gap opening and quenching were predicted for the graphene superlattice with two symmetrical sublattices and those with two unsymmetrical sublattices, respectively. Theoretical analysis based on the spinor Hamiltonian showed that the correlations between pseudospins of Dirac fermions in graphene and the applied external potential, and the potential-induced intervalley scattering, play important roles in energy-gap opening and quenching.
我们使用基于密度泛函理论（DFT）的第一性原理方法和基于广义有效旋量哈密顿量的理论方法研究了周期性外势对石墨烯中电荷载流子性质的影响。DFT 计算是在包括周期性外势影响的修正 Kohn-Sham 程序中进行的。对于具有两个对称子晶格和两个不对称子晶格的石墨烯超晶格，分别预测了意想不到的能带隙的开启和猝灭。基于旋量哈密顿量的理论分析表明，石墨烯中狄拉克费米子的赝自旋与外加外势之间的相关性以及外势诱导的谷间散射在能隙的开启和猝灭中起着重要作用。
