Valence Fluctuations Revealed by Magnetic Field and Pressure Scans: Comparison with Experiments in YbXCu4 (X=In, Ag, Cd) and CeYIn5 (Y=Ir, Rh)
Abstract
The mechanism of how critical end points of the first-order valence transition (FOVT) are controlled by a magnetic field is discussed. We demonstrate that critical temperature is suppressed to be a quantum critical point (QCP) by a magnetic field. This results explain the field dependence of the isostructural FOVT observed in Ce metal and YbInCu4. Magnetic field scan can make the system reenter in a critical valence fluctuation region. Even in intermediate-valence materials, the QCP is induced by applying a magnetic field, at which magnetic susceptibility also diverges. The driving force of the field-induced QCP is shown to be a cooperative phenomenon of the Zeeman effect and the Kondo effect, which creates a distinct energy scale from the Kondo temperature. The key concept is that the closeness to the QCP of the FOVT is vital in understanding Ce- and Yb-based heavy-fermions. This explains the peculiar magnetic and transport responses in CeYIn5 (Y=Ir, Rh) and metamagnetic transition in YbXCu4 for X=In as well as the sharp contrast between X=Ag and Cd.
- Publication:
-
Journal of the Physical Society of Japan
- Pub Date:
- October 2009
- DOI:
- 10.1143/JPSJ.78.104706
- arXiv:
- arXiv:0906.4163
- Bibcode:
- 2009JPSJ...78j4706W
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- 14 pages, 9 figures, OPEN SELECT in J. Phys. Soc. Jpn