The full counting statistics of electron transport through two coherent strongly serially
coupled quantum dots (QDs) is theoretically studied based on an efficient
particle-number-resolved master equation. When the coupling of the double-QD system with
the incident-electrode is stronger than that with the outgoing-electrode, it is
demonstrated that the super-Poissonian noise bias voltage range, which originates from the
so-called dynamical channel blockade mechanism, depends sensitively on the types of
energy-level detuning, which means that the super-Poissonian noise bias voltage range can
be controlled by energy-level detuning and can be used to reveal the internal energy level
structure of the considered double-QD system. For the on-site energy of the left QD
coupled to incident-electrode is larger than that of the right QD coupled to
out-electrode, i.e.,
ϵL > ϵR,
a strong negative differential conductance (NDC) is observed in a certain energy-level
detuning range and this level detuning range depends on the interdot Coulomb interaction,
which suggests a tunable NDC device; whereas for
ϵL < ϵR
the magnitude of NDC is relatively very weak, and the corresponding shot noise is not
always enhanced and even decreased at appropriate energy-level detuning. Moreover, the
super-Poissonian behaviors of skewness and kurtosis are found to be more sensitive to the
effective competition between the fast-and-slow transport channels than shot noise.
