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

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.Comment: 9 pages, 7 Figures, version as published in PR

Basic and applied scientific research, innovation and economic development

Basic scientific research can be defined as fundamental, investigative research, theoretical or experimental, to advance knowledge without a specifically envisaged practical applications. It is the quest for new knowledge and the exploration of the unknown. Basic research is driven purely by curiosity and a desire to expand our knowledge. On the contrary, applied research is used to answer specific questions that have direct applications to the society. Basic and applied research is a continuum and they are inter-dependent. The demarcation between basic research and applied research is not at all clear cut. Most scientific research, whether in the academic world or in industry, is a hybrid leading to new knowledge generation and subsequent exploitation. The integration of basic and applied research is crucial to problem-solving, innovation and development of products and processes.</p