Relativistic band-structure calculations for CeTIn(T=Ir and Co) and analysis of the energy bands by using tight-binding method

Maehira, Takahiro; Hotta, Takashi; Ueda, Kazuo; Hasegawa, Akira*

In order to investigate electronic properties of recently discovered heavy fermion superconductors CeTIn (T=Ir and Co), we employ the relativistic linear augmented-plane-wave (RLAPW) method to clarify the energy band structures and Fermi surfaces of those materials.The obtained energy bands mainly due to the large hybridization between Ce and In 5 states well reproduce the Fermi surfaces consistent with the de Haas-van Alphen experimental results. For the purpose, we construct a tight-binding model for CeTIn by including - and - hoppings as well as - hybridization, which are expressed by the Slater-Koster integrals, determined by the direct comparison with the band-calculation result. Similarity and difference between CeIrIn and CeCoIn are discussed based on the obtained tight-binding model, suggesting a significant importance of the effect of crystalline electric field to understand the difference in electronic properties among CeTIn.