Influence of symmetry on the conductance of a graphene double dot

We numerically study the transport behavior of a graphene cavity delimited by two constrictions and divided into two dots by the tunnel barrier induced by the electrostatic action of a negatively biased gate. Performing an analysis, based on an envelope function approach, of the dependence of the conductance on the position of the tunnel barrier, we observe a maximum when the barrier is at the middle of the cavity, an effect similar, even though less pronounced, to that recently studied in devices based on semiconductor heterostructures.