title: Magnetic-field control of quantum critical points of valence transition.
abstract: We study the mechanism of how critical end points of first-order valence transitions are controlled by a magnetic field. We show that the critical temperature is suppressed to be a quantum critical point (QCP) by a magnetic field, and unexpectedly, the QCP exhibits nonmonotonic field dependence in the ground-state phase diagram, giving rise to the emergence of metamagnetism even in the intermediate valence-crossover regime. The driving force of the field-induced QCP is clarified to be cooperative phenomena of the Zeeman and Kondo effects, which create a distinct energy scale from the Kondo temperature. This mechanism explains the peculiar magnetic response in CeIrIn(5) and the metamagnetic transition in YbXCu(4) for X=In as well as the sharp contrast between X=Ag and Cd.
authors.affiliation: Department of Applied Physics, University of Tokyo, Tokyo, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Watanabe
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tsuruta
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Miyake
authors.forename: Jacques
authors.initials: J
authors.lastname: Flouquet