Conductance peak splitting in hole transport through a SiGe double quantum dot

We have observed the splitting of Coulomb oscillation peaks in coupled Si0.9Ge0.1 double quantum dots at 4.2 K. The quantum dots are formed by trench isolation, which means that the dots can be made much smaller than possible with the surface-gated approach. A dot diameter of 50 nm or less increases the charging energy and, therefore, the operating temperature of the device compared to previous approaches. A simulation of the results using parameters calculated from the lithographic dimensions of the device shows that a good fit to the experimental data can be achieved with a realistic interdot capacitance value.