title: Doping a correlated band insulator: a new route to half-metallic behavior.
abstract: We demonstrate in a simple model the surprising result that turning on an on-site Coulomb interaction U in a doped band insulator leads to the formation of a half-metallic state. In the undoped system, we show that increasing U leads to a first order transition at a finite value UAF between a paramagnetic band insulator and an antiferomagnetic Mott insulator. Upon doping, the system exhibits half-metallic ferrimagnetism over a wide range of doping and interaction strengths on either side of UAF. Our results, based on dynamical mean field theory, suggest a new route to half metallicity, and will hopefully motivate searches for new materials for spintronics.
authors.affiliation: Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India.
authors.forename: Arti
authors.initials: A
authors.lastname: Garg
authors.affiliation: Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560 012, India and JNCASR, Jakkur, Bangalore 560 064, India.
authors.forename: H R
authors.initials: HR
authors.lastname: Krishnamurthy
authors.affiliation: Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Mohit
authors.initials: M
authors.lastname: Randeria