Electronic states and metal–insulator transition in the triangular lattice d–p model for layered cobaltates

✍ Scribed by Yoshiaki Ōno

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 148 KB
• Volume: 460-462
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2007.03.212

✦ Synopsis

We investigate the electronic state of the 11 band d-p model on the two-dimensional triangular lattice simulating a CoO 2 plane in the layered cobalt oxides such as Na x CoO 2 and Na x CoO 2 AE yH 2 O. The tight-binding parameters are determined so as to fit the LDA band structure. Using the slave boson approach together with the 1/N expansion method, we obtain the renormalized quasiparticle bands, where the a 1g band with a large hole Fermi surface is largely renormalized due to the strong correlation effect, while the e 0 g bands with six hole pockets are almost unchanged. We also discuss the metal-insulator transition (MIT) with varying the d-p charge transfer energy D, and find that the MIT takes place at a critical value D c = 4.01 eV.