Grüneisen ratio at the Kondo breakdown quantum critical point

الأصل · EN

We show that the scenario of multi-scale Kondo breakdown quantum critical point (QCP) 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 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 K and 10 K. We discuss how the Grüneisen ratio is a key measurement to discriminate between the Kondo breakdown and spin-density wave theories.