Qin, H. and Holleitner, A. W. and Wegscheider, Werner and Hüttel, Andreas K. and Blick, Robert H. and Bichler, Max and Eberl, Karl and Kotthaus, Jörg P.
Probing coherent electronic states in double quantum dots.
physica status solidi (c) 1 (8), pp. 2094-2110.
Experimental results on both serial and parallel double quantum dots are presented. The quantum dots are realized in the two-dimensional electron gas of an AlGaAs/GaAs heterostructure. By varying the inter-dot tunnel barriers, double quantum dots are tuned from the weak coupling limit to the strong coupling case. In serial double quantum dots, bonding and anti-bonding molecular states are probed by both direct tunneling and photon-assisted tunneling spectroscopy. In parallel double quantum dots, a coherent transport through the whole structure is verified through Aharonov-Bohm oscillations in the magnetotransport data. Furthermore, coherent molecular states are read out by a cotunneling current. Finally, a scheme for preparing and measuring a solid-state quantum bit is discussed.