  Kondo effect offers an important paradigm to understand strong correlated
many-body physics. Although under intensive study, some of important properties
of Kondo effect, in systems where both itinerant coupling and localized
coupling play significant roles, are still elusive. Here we report evolution
and universality of two stage Kondo effect, the simplest form where both
couplings are important using single molecule transistor devices incorporating
Manganese phthalocyanine molecules. Kondo temperature T* of two-stage Kondo
effect evolves linearly against effective interaction of involved two spins.
Observed Kondo resonance shows universal quadratic dependence with all
adjustable parameters: temperature, magnetic field and biased voltages. The
difference in nonequilibrium conductance of two stage Kondo effect to spin 1/2
Kondo effect is also identified. Messages learned in this study fill in
directive experimental evidence of evolution of two-stage Kondo resonance near
quantum phase transition point, and help in understanding sophisticated
molecular electron spectroscopy in strong correlation regime.
