Density-functional theory and strong interactions: Orbital ordering in Mott-Hubbard insulators

✍ Scribed by Liechtenstein, A. I.; Zaanen, J.

• Book ID: 111931123
• Publisher: The American Physical Society
• Year: 1995
• Tongue: English
• Weight: 260 KB
• Volume: 52
• Category: Article
• ISSN: 1098-0121
• DOI: 10.1103/physrevb.52.r5467

✦ Synopsis

Evidence is presented that within the density-functional theory orbital polarization has to be treated on an equal footing with spin polarization and charge density for strongly interacting electron systems. Using a basis-set independent generalization of the LDA+U functional, we show that electronic orbital ordering is a necessary condition to obtain the correct crystal structure and parameters of the exchange interaction for the Mott-Hubbard insulator KCuF3 .

According to the Hohenberg-Kohn theorem and its exten- sions, the ground state of an electron system should be uniquely determined by the charge density as well as all other quantities with nonzero macroscopic expectation val- ues, like magnetic order parameters (spin density). Here we propose that the failure of the local approximation to (spin-) density-functional theory [L(S)DA] in the description of Mott-Hubbard insulators (MHI) is fundamentally related to the neglect of one of these averaged quantities, the polarization of the remnants of atomic angular momentum.