Antiferromagnetism and Kondo screening on a honeycomb lattice*
Lin Heng-Fu†, Hong-Shuai Tao, Guo Wen-Xiang, Liu Wu-Ming
       
The spectral function of the conduction electrons ρ c ( ω ) ((a1)–(d1)), and local electrons ρ f ( ω ) ((a2)–(d2)) with U = 4.0, 8.0 and V = 0.2, 1.0, 2.0, 4.0 for temperature T = 1/5,1/20. When V = 0.2, we have a set of individual local moments decoupled from the conduction band, the ρ c ( ω ) and ρ f ( ω ) are very different. At intermediate V = 1.0, the ρ c ( ω ) and ρ f ( ω ) have a peak at the Fermi level at high temperature T = 1/5, and a small gap at low temperature 1/20. The gap formation means that the system shows the long-range antiferromagnetic order. At large V = 2.0, 4.0, the system goes to the Kondo insulator, the ρ c ( ω ) and ρ f ( ω ) have a large insulating gap at all temperatures in the Fermi level, the gap grows with the increase of V .