Magnetic-Field Control of Quantum Critical Points of Valence Transition

TL;DR

This paper investigates how magnetic fields influence valence transition critical points, revealing a nonmonotonic quantum critical point behavior and its connection to metamagnetism in heavy fermion compounds.

Contribution

It uncovers the mechanism by which magnetic fields induce quantum critical points in valence transitions, highlighting the cooperative role of Zeeman and Kondo effects.

Findings

Magnetic field suppresses critical temperature to a QCP.

QCP exhibits nonmonotonic field dependence.

Field-induced QCP explains magnetic responses in specific compounds.

Abstract

We study the mechanism 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 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 Zeeman effect and Kondo effect, which create a distinct energy scale from the Kondo temperature. This mechanism explains peculiar magnetic response in CeIrIn5 and metamagnetic transition in YbXCu4 for X=In as well as sharp contrast between X=Ag and Cd.