  We investigate the effect of contact geometry on the instantaneous
thermoelectric response of a quantum dot pushed suddenly into the Kondo regime
via a gate voltage using time dependent non-crossing approximation and linear
response Onsager relations. We utilize graphene and metal contacts for this
purpose. Instantaneous thermopower displays sinusoidal oscillations whose
frequency is proportional to the energy separation between the van Hove
singularity in the contact density of states and Fermi level for both cases
regardless of the asymmetry factor at the onset of Kondo timescale. The
amplitude of the oscillations increases with decreasing temperature saturating
around the Kondo temperature. We also calculate the instantaneous figure of
merit and show that the oscillations taking place at temperatures above the
Kondo temperature are enhanced more than the ones occurring at lower
temperatures due to the violation of the Wiedemann-Franz law. Graphene emerges
as a more promising electrode candidate than ordinary metals in single electron
devices since it can minimize these oscillations.
