Emergence of heavy quasiparticles from a massless Fermi sea: Optical conductivity

Article

关键词: SINGLE DIRAC CONE;    KONDO-LATTICE;    SYSTEMS;    GAP;    TRANSITION;    INSULATOR;    BEHAVIOR;    SURFACE;    METALS;    LIQUID;   

DOI  :  10.1103/PhysRevB.91.205109

来源: SCIE

【 摘 要 】

We study the density of states and the optical conductivity of a Anderson lattice which is immersed in a massless Dirac Fermi sea, as characterized by a linear dispersion relation. As a result of the hybridization V with the f-electron levels, the pseudogap in the conduction band becomes duplicated and is shifted both into the upper and lower quasiparticle bands. We find that, due to the linear dispersion of the Dirac fermions, the Kondo-insulator gap is observable in the optical conductivity in contrast to the Kondo lattice system in a conventional conduction band. The reason is that the Kondo-insulator gap becomes a direct gap in the Dirac Fermi sea, while it is a strongly indirect gap in conventional Anderson lattices. The gap Delta(gap)(T) depends on temperature due to Kondo correlations. We find that the optical conductivity attains two peaks. It is vanishing exactly at 2b(T)V where b(T)V is the effective hybridization between the Dirac electrons and the f electrons, which depends on temperature T.

【 授权许可】

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