Anisotropic energy scale for degenerate Fermi and non-Fermi liquids near a quantum critical phase transition inYbRh2Si2

Abstract

Based on $^{29}\mathrm{Si}$ nuclear spin-lattice relaxation time $({T}_{1})$ data on a single crystal of ${\mathrm{YbRh}}_{2}{\mathrm{Si}}_{2}$, the coexisting Fermi liquid and non-Fermi liquid states around the quantum critical phase transition have been found to be sensitive to the direction of the applied magnetic field. Augmented scaling analysis shows that the anisotropic characteristic temperature and field are roughly ten times larger for $H\ensuremath{\parallel}c$ than for $H\ensuremath{\parallel}a$, consistent with a previously obtained anisotropic phase diagram.