Low-temperature thermodynamics of the heavy-fermion metal YbRh2(Si1-xGex)2 within a topological scenario for the quantum critical point

Abstract

We describe a topological scenario for the quantum critical point signaled by a divergent density of states at zero temperature, in which the Landau quasiparticle picture survives but the topology of the Fermi surface is altered. Predictions of this scenario for thermodynamic properties of the heavy-fermion metal YbRh2(Si1−xGex)2 are shown to be in agreement with available experimental data, whereas the conventional scenario based on critical fluctuations of a collective mode fails to explain these properties.