Artificial Atoms'' in Magnetic Fields: Wave-Function Shaping and Phase-Sensitive Tunneling

We demonstrate the possibility to influence the shape of the wave functions in semiconductor quantum dots by the application of an external magnetic field B-z. The states of the so-called p shell, which show distinct orientations along the crystal axes for B-z = 0, can be modified to become more and more circularly symmetric with an increasing field. Their changing probability density can be monitored using magnetotunneling wave function mapping. Calculations of the magnetotunneling signals are in good agreement with the experimental data and explain the different tunneling maps of the p(+) and p(-) states as a consequence of the different sign of their respective phase factors.