KO2: Realization of Orbital Ordering in a p-Orbital System

Nandy, Ashis Kumar and Mahadevan, Priya and Sen, Prasenjit and Sarma, DD (2010) KO2: Realization of Orbital Ordering in a p-Orbital System. In: Physical Review Letters, 105 (5).

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Abstract

KO2 is a molecular solid consisting of oxygen dimers. K present in the lattice donates an electron which goes on to occupy the O p levels.As the basic electronic structure is similar to that of an oxygen molecule, except for broadening due to solid state effects, KO2 represents the realization of the doping of oxygen molecules arranged in a lattice. These considerations alone result in magnetism with high ordering temperatures as our calculations reveal. However, we find that the high temperature structure is unstable to an orbital ordering (OO) transition. The microscopic considerations driving the OO transition, however, are electrostatic interactions instead of the often encountered superexchange driven ordering within the Kugel-Khomskii model often used to describe the OO. This OO transition is also found to preclude any possibility of high magnetic ordering temperatures, which otherwise seemed possible.

Item Type:	Journal Article
Publication:	Physical Review Letters
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to The American Physical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	24 Aug 2010 04:56
Last Modified:	19 Sep 2010 06:14
URI:	http://eprints.iisc.ac.in/id/eprint/31319

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