Triple quantum dots: Two path transport and electrostatic stability diagram

We present analysis of measurements on a triple quantum dot with a two path setup. The electron transport along both paths is recorded as well as charging data measured with a quantum point contact. The results are compared with an electrostatic model. This model allows for the full visualization of the three dimensional stability diagram for triple quantum dots. It is found that this diagram contains a central diamond shaped plane at which one specific quantum cellular automata (QCA) process occurs. Moreover quadruple points are found with four degenerate charge configurations. The QCA process defines the quadruple points and limits their number to six.