title: Gap-anisotropic model for the narrow-Gap kondo insulators
abstract: A theory is presented which accounts for the dynamical generation of a hybridization gap with nodes in the Kondo insulating materials CeNiSn and CeRhSb. We show that Hund's interactions acting on virtual 4f(2) configurations of the cerium ion can act to dynamically select the shape of the cerium ion by generating a Weiss field which couples to the shape of the ion. In low symmetry crystals where the external crystal fields are negligible, this process selects a nodal Kondo semimetal state as the lowest energy configuration.
authors.affiliation: Department of Physics & Astronomy, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208, USA.
authors.initials: J
authors.lastname: Moreno
authors.initials: P
authors.lastname: Coleman