First principles electronic structure of spinel LiCr2O4: A possible half-metal?

TL;DR

This study uses first-principles calculations to explore the electronic structure and potential half-metallicity of the hypothetical spinel LiCr2O4, revealing its magnetic properties and structural characteristics.

Contribution

It provides the first detailed electronic and magnetic analysis of LiCr2O4, a hypothetical compound, highlighting its potential as a half-metal and comparing it with related materials.

Findings

LiCr2O4 is predicted to be magnetic and a candidate half-metal.

The electronic structure differs from CrO2 due to topology and oxidation state.

Magnetism and half-metallicity depend on the cubic crystal parameters.

Abstract

We have employed first-principles electronic structure calculations to examine the hypothetical (but plausible) oxide spinel, LiCr2O4 with the d^{2.5} electronic configuration. The cell (cubic) and internal (oxygen position) structural parameters have been obtained for this compound through structural relaxation in the first-principles framework. Within the one-electron band picture, we find that LiCr2O4 is magnetic, and a candidate half-metal. The electronic structure is substantially different from the closely related and well known rutile half-metal CrO2. In particular, we find a smaller conduction band width in the spinel compound, perhaps as a result of the distinct topology of the spinel crystal structure, and the reduced oxidation state. The magnetism and half-metallicity of LiCr2O4 has been mapped in the parameter space of its cubic crystal structure. Comparisons with superconducting LiTi2O4 (d^{0.5}), heavy-fermion LiV2O4 (d^{1.5}) and charge-ordering LiMn2O4 (d^{3.5}) suggest the effectiveness of a nearly-rigid band picture involving simple shifts of the position of E_F in these very different materials. Comparisons are also made with the electronic structure of ZnV2O4 (d^{2}), a correlated insulator that undergoes a structural and antiferromagnetic phase transition.