TUE-CMS

Abstract: Turning on strong electron correlations in a normal metal often leads to interesting phases like Mott Insulators, high Tc superconductors, magnets and non Fermiliquids. But the effect of correlations in band insulators are less explored. We study effects of an onsite Hubbard interaction U on a band insulator and find a novel interaction driven route to a half-metallic (HM) ferrimagnetic state. Half-metals are an interesting class of materials where electrons with one spin polarization behave as in a metal while those with the opposite spin polarization behave as in an insulator. They have applications in spintronics for generating spin-polarized currents and for tunnel magnetoresistance devices. In this talk I will present a very surprising result with a novel interaction-driven route to half- metallic ferrimagnetic state, which is quite distinct from the mechanisms in well-known half-metallic materials.