Fig. 1: Tr-MERTS setup and spectra.
a The tunnel device consists of two 2DESs separated by a thin tunnel barrier (see Methods). We apply a sequence of electrical pulses across the device and detect the image charge of the tunneled electrons14,15,16. b Schematic representation of the pulse sequence. The first “pump” pulse ejects electrons from the source and pumps these electrons into the target. The second “delay” pulse turns off tunneling between the source and target during the time delay (t). The last “probe” pulse measures the current (I) flowing into the target over a short period of time14. c A cartoon depicting a pumping process. During the pump pulse, electrons in the N = 0 LL in the source are pumped into a higher LL in the target. d A sequence of Tr-MERTS spectra measured as a function of t before and after pumping the N = 1 LL at B⊥ = 5.1 T and T = 50 mK. Arrows indicate transient tunneling current. ΔE arises from a charging effect that is proportional to the density of pumped electrons (see Methods). Yellow features below ΔE are not transient and result from tunneling between the N = 0 LLs in the source and target (See Supplementary Fig. 5 for a detailed explanation).
