attoPUBLICATIONS attoCATALOG-2017/18 | Page 141

Selected Applications 1- X 50mK attoCFM II 1.2983 1.2982 1.2981 Confocal Microscopy on Quantum Dots at 50 mK 0 1.2983 1.2983 80 100 1.29810 40 60 gate voltage (mV) 1.29812 1- X 50mK 1.29808 1.2982 1.2982 1.29806 1.2981 1.2981 0 0 20 20 20 40 60 40 60 gate voltage (mV) gate voltage (mV) 80 80 1.29804 100 100 15 30 gate voltage (mV) A customized attoCFM II module was implemented into a dilution re- frigerator for the detailed investigation of quantum dots in an ultra-low temperature environment and magnetic fields of up to 7 T. The figure shows differential transmission measurements on a InAs quantum dot embedded in a GaAs matrix at 50 mK. The pronounced deviation from the lineshape as expected from the quantum confined Stark effect is due to many-particle interactions. 45 [1] C. Latta, et al., Nature 474, 627 (2011) 1.29812 1.29810 1.29808 1.29806 1.29804 15 30 gate voltage (mV) 45 Photocurrent Measurements on Graphene Devices Spatially resolved photocurrent measurements on a graphene field-ef- fect device in the QHE regime are presented to study the distribution of Landau levels and its relation with macroscopic transport character- istics [1]. The exceptional stability and the ease of use of the attoCFM microscope greatly facilitated these measurements and allowed for mea- suring working devices in magnetic fields from -9 to +9 T. [1] G. Nazin, Y. Zhang, L. Zhang, E. Sutter, P. Sutter, Nature Physics 6, 870–874 (2010) attoMICROSCOPY Sophisticated Tools for Science PAGE 139