Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan.
Phys Rev Lett. 2010 Jul 16;105(3):037203. doi: 10.1103/PhysRevLett.105.037203. Epub 2010 Jul 14.
We investigate Dirac fermions in the antiferromagnetic metallic state of iron-based superconductors. Deriving an effective Hamiltonian for Dirac fermions, we reveal that there exist two Dirac cones carrying the same chirality, contrary to graphene, compensated by a Fermi surface with a quadratic energy dispersion as a consequence of a nontrivial topological property inherent in the band structure. We also find that the presence of the Dirac fermions gives the difference of sign-change temperatures between the Hall coefficient and the thermopower. This is consistent with available experimental data.
我们研究了铁基超导体反铁磁金属态中的狄拉克费米子。通过推导出狄拉克费米子的有效哈密顿量，我们揭示了存在两个具有相同手性的狄拉克锥，这与石墨烯不同，这是由能带结构中固有的非平凡拓扑性质导致的二次色散费米面补偿的。我们还发现，狄拉克费米子的存在导致了霍尔系数和热功率的 sign-change 温度之间的差异。这与现有的实验数据是一致的。
