Pressure dependence of the characteristic Kondo temperature of YbRh2Si2

Several anomalies were observed in the electrical resistivity of YbRh2Si2 as a function of the pressure,namely, TN and maxima at Tmax and Tmaxlow. The negative logarithmic temperature dependence of the electrical resistivity ρ(T) for T > Tmax and for T > Tmaxlow indicates that a combined incoherent Kondo scattering on the ground state and the excited CEF-levels are responsible for these anomalies. Therefore, we attempt to infer the pressure dependence of the characteristic Kondo temperature TK(p) of YbRh2Si2 by means of a simple model that considers the effect of the orbital degeneracy on a dense Kondo state and the compressible Kondo lattice model. TK(p) is compared with the pressure dependence of the Neel temperature TN(p), in particular in the pressure range 4 GPa<p<9 GPa where TN(p) shows a quasi-pressure independent behavior. (orig.)