title: Grüneisen ratio at the kondo-breakdown quantum critical point.
abstract: We show that the scenario of a multiscale Kondo-breakdown quantum critical point gives rise to a divergent Grüneisen ratio with an anomalous exponent 0.7. In particular, we fit the experimental data of YbRh2(Si0.95Ge0.05)2 for a specific heat, thermal expansion, and Grüneisen ratio based on our simple analytic expressions. A reasonable agreement between the experiment and theory is found for the temperature range between 0.4 and 10 K. We discuss how the Grüneisen ratio is a key measurement to discriminate between the Kondo-breakdown and spin-density wave theories.
authors.affiliation: Institut de Physique Théorique, CEA, IPhT, CNRS, URA 2306, F-91191 Gif-sur-Yvette, France.
authors.forename: K-S
authors.initials: KS
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Benlagra
authors.forename: C
authors.initials: C
authors.lastname: Pépin