The Fano factor stability diagram of a $C_{3v}$ symmetric triangular quantum dot is analyzed for increasing electron fillings $N$. At low filling, conventional Poissonian and sub-Poissonian behavior is found. At larger filling, $N\ge 2$, a breaking of the electron-hole symmetry is manifested in super-Poissonian noise with a peculiar bias voltage dependence of the Fano factor at Coulomb and interference blockade. An analysis of the Fano map unravels a nontrivial electron-bunching mechanism arising from the presence of degenerate many-body states combined with orbital interference and Coulomb interactions. An expression for the associated dark states is provided for generic $N$.

• Received 6 October 2016
• Revised 10 February 2017

DOI:https://doi.org/10.1103/PhysRevB.95.115133