Fig. 2: ν dependence of Tr-MERTS spectra.
a 4D visualization of Tr-MERTS spectrum measured as functions of E, Δk, and ν. The spectrum is taken immediately after pumping the N = 1 LL at B⊥ = 6.5 T and T = 50 mK. The vertical axis is E, proportional to the height of the probe pulse. Horizontal and depth axes are ν of the target and Δk, respectively. Each surface shows a constant Δk, ν, or E cut. Colors represent the intensity of the tunneling current. The ν of the source is fixed at 0.35. b–d Tr-MERTS spectra measured as functions of E and t at Δk = 0.014 Å−1. e ν dependence of relaxation time τ. The red dashed line is a fit based on Fermi’s golden rule for decays, inversely proportional to the density of states (ρf) available in the lower energy level. The deviation from the fit grows at ν > 1 and ν < 5/3 (see black arrows) due to a sharp change in the ground-state spin polarization17,18. The inset illustrates a slow relaxation process involving spin-flips. Red and grey horizontal lines represent the occupied and unoccupied states in the N = 0 LL, respectively.
