SINGLE-ELECTRON CHARGING IN DOUBLE AND TRIPLE QUANTUM DOTS WITH TUNABLE COUPLING

We report low-temperature tunneling measurements at zero magnetic fiel d through double and triple quantum dots with adjustable interdot coup ling, fabricated in a GaAs/AlGaAs heterostructure. As the coupling is increased, Coulomb blockade conductance peaks split into two (double d ot) or three (triple dot) peaks each. The splitting tracks closely the measured tunnel conductance and experimentally determines the total i nteraction energy. Coupled double and triple dots with different gate capacitance show quasiperiodic beating.